A baseball of mass m is thrown upward with some initial speed. A gravitational force is exerted on the ball
At all points in its motion
At all points in its motion except at the highest point
At no points in its motion
Only at downward part of its direction
The kinetic friction will always be
Less than static friction
Greater than static friction
Equal to the static friction
Negative
The unit of coefficient of friction in SI system is
Newton
Dyne
None of these
No unit
Whenever a constant force is applied on a body then it will move with __________.
Constant Speed
Constant Velocity
Constant Acceleration
None of them
Power is a __________.
Scalar Quantity
Vector Quantity
Rate of force
The dot product of force and velocity is called __________.
Work
Power
Energy
Momentum
When the force and displacement are perpendicular to each other, then work is __________.
zero
Maximum
Depends on force magnitude
Centripetal acceleration and tangential acceleration are always __________
Parallel to Each other, but in opposite direction
Perpendicular to each other
Parallel to Each other, but in the same direction
The dimensions of angular momentum are __________.
MLT-1
MLT-2
ML2T-2
ML2T-1
The moment of inertia of a wheel about its axle does not depend upon its:
Diameter
Mass
distribution of mass
speed of rotation
Two waves have the same frequency. Which wave characteristic must also be identical for both waves?
Phase
Amplitude
Intensity
Period
A mechanical wave generally does NOT
move the medium from one place to another
move through a medium
move through solids
disturb the medium
The moment of inertia of a body depends on
the angular velocity
the angular acceleration
the mass distribution
the torque acting on the body
A skater can spin faster by pulling in her arms closer to her body or spin slower by spreading her arms out from her body. This is due to
Conservation of momentum
Conservation of energy
Newton’s third law
Conservation of angular momentum
The SI units for Coulomb constant ke are:
N·m2/C2
N·m/C
N·m/C2
m2/C2
No correct answer
The electric field vector E can be expressed as:
E=Fe/q
E=Fe/q2
E=Fe·q
E=Fe·q2
Which statements are correct?
Charges of opposite sign attract one another and charges of the same sign repel one another. Total charge in an isolated system is conserved. Charge is quantized.
Charges of opposite sign repel one another and charges of the same sign attract one another. Total charge in an isolated system is conserved. Charge is quantized.
Charges of opposite sign attract one another and charges of the same sign repel one another. Total charge in an isolated system is not conserved. Charge is quantized.
Charges of opposite sign repel one another and charges of the same sign attract one another. Total charge in an isolated system is ot conserved. Charge is not quantized.
Conductors are materials in which electrons move freely. Insulators are materials in which electrons do not move freely.
Insulators are materials in which electrons move freely. Conductors are materials in which electrons do not move freely.
Conductors are materials in which electrons don’t move freely. Insulators are materials in which electrons move freely.
All answers are correct
If the electric field is uniform and makes an angle θ with the normal to a surface of area A, the electric flux through the surface is:
ΦE=EAcosθ
ΦE=EAsinθ
ΦE=Acosθsinθ
ΦE=Ecosθ
Gauss’s law says that the net electric flux ΦE through any closed gaussian surface is equal to:
ΦE=qin/ε0
ΦE=qin·ε0
ΦE= ε0/qin
ΦE=qinqout/ε0
A conductor in electrostatic equilibrium has the following properties:
1. The electric field is zero everywhere inside the conductor. 2. Any net charge on the conductor resides entirely on its surface. 3. The electric field just outside the conductor is perpendicular to its surface and has a magnitude σ/ε0, where σ is the surface charge density at that point. 4. On an irregularly shaped conductor, the surface charge density is greatest where the radius of curvature of the surface is the smallest.
1. The electric field is zero everywhere inside the conductor. 2. Any net charge on the conductor resides partially on its surface, partially inside the conductor. 3. The electric field just outside the conductor is parallel to its surface and has a magnitude σ/ε0, where σ is the surface charge density at that point. 4. On an irregularly shaped conductor, the surface charge density is greatest where the radius of curvature of the surface is the smallest.
1. The electric field is non zero everywhere inside the conductor. 2. Any net charge on the conductor resides entirely on its surface. 3. The electric field just outside the conductor is perpendicular to its surface and has a magnitude σ/ε0, where σ is the surface charge density at that point. 4. On an irregularly shaped conductor, the surface charge density is greatest where the radius of curvature of the surface is the biggest.
1. The electric field is zero everywhere inside the conductor. 2. Any net charge on the conductor resides entirely inside the conductor. 3. The electric field just outside the conductor is perpendicular to its surface and has a magnitude σ/ε0, where σ is the surface charge density at that point. 4. On an irregularly shaped conductor, the surface charge density is smallest where the radius of curvature of the surface is the smallest.
The potential difference between two points A and B in a uniform electric field E, where s (d=|s|) is a vector that points from A to B and is parallel to E is:
∆V=-Ed
∆V=0
∆V=Ed
∆V=-Edsinθ
An equipotential surface is one on which all points are at the same electric potential. Equipotential surfaces are perpendicular to electric field lines.
An equipotential surface is one on which all points are at the same electric potential. Equipotential surfaces are parallel to electric field lines.
An equipotential surface is one on which all points are not at the same electric potential. Equipotential surfaces are perpendicular to electric field lines.
An equipotential surface is one on which all points are at the same electric potential. Equipotential surfaces are perpendicular to gravitation field lines.
The SI unit of capacitance is:
C/V
V/C
C/V2
C/V·m
The equivalent capacitance of a parallel combination of capacitors is:
Ceq=C1+C2+C3+...
1/Ceq=1/C1+1/C2+1/C3+...
Ceq=C1=C2=C3=...
Ceq=C1·C2·C3·...
If two or more capacitors are connected in series, the equivalent capacitance of the series combination is given by:
The electric dipole moment p of an electric dipole has a magnitude:
p=2aQ
p=Q
p=Q2
p=-2aQ
The torque acting on an electric dipole in a uniform electric field E is:
τ=pxE
τ=p·E
τ=p/E
τ=qpxE
The potential energy of the system of an electric dipole in a uniform external electric field E is:
U=- p·E
U= pxE
U= p·E
U= p/E
The average current in a conductor is related to the motion of the charge carriers through the relationship:
Iav=nqvdA
Iav=nqvd
Iav=qvdA
Iav=nq/vdA
The magnitude of the current density J in a conductor is:
J=I/A
J=IA
J=IA2
J=I2/A
Ohm’s law in the differential form is:
J=σE
I=U/R
I=R/U
J=σ/E
Ohm’s law in the integral form is:
The resistance R of a conductor is defined as:
R=∆V/I
R=σE
R=∆V·I
R=I/∆V
The power supplied to the element, is:
P=I∆V
P=I/∆V
P=I2∆V
P=I∆V2
The power delivered to a resistor can be defined as:
P=I2R
P=IR
P=IR2
P=I2/R
The equivalent resistance of a set of resistors connected in series is:
Req=R1+R2+R3+...
1/Req=1/R1+1/R2+1/R3+...
Req=1/(R1+R2+R3+...)
Req=R1+R2+R3+...R4
Circuits involving more than one loop are conveniently analyzed with the use of Kirchhoff’s rules:
1. The sum of the currents entering any junction in an electric circuit must equal the sum of the currents leaving that junction. 2. The sum of the potential differences across all elements around any circuit loop must be zero.
1. The product of the currents entering any junction in an electric circuit must equal the sum of the currents leaving that junction. 2. The sum of the potential differences across all elements around any circuit loop must be constant.
1. The sum of the currents at any circuit loop must be zero. 2. The sum of the potential differences across all elements around any circuit loop must be zero.
1. The sum of the currents entering any junction in an electric circuit must equal the sum of the currents leaving that junction. 2. The product of the potential differences across all elements around any circuit loop must be zero.
Two objects, with different sizes, masses, and temperatures, are placed in thermal contact. Energy travels
From the larger object to the smaller object,
From the object with more mass to the one with less,
From the object at higher temperature to the object at lower temperature,
Energy doesn’t travel,
From the object at lower temperature to the object at higher temperature,
On a day when the temperature reaches 50°F, what is the temperature in degrees Celsius and in kelvins?
50 C, 323 K,
40 C, 313 K,
30 C, 303 K,
20 C, 293 K,
10 C, 283 K.
A helium-filled rubber balloon is left in a car on a cold winter night. Compared to its size when it was in the warm car the afternoon before, the size the next morning is
Larger
Smaller
Unchanged
The first law of thermodynamics can be given as ________.
for any spontaneous process, the entropy of the universe increases
the entropy of a pure crystalline substance at absolute zero is zero
ΔS = Q/T at constant temperature
ΔE = Q + W
The second law of thermodynamics can be given as __________
Which of the following is not a state function?
Pressure
Volume
Temperature
Mole
Two containers hold an ideal gas at the same temperature and pressure. Both containers hold the same type of gas but container B has twice the volume of container A. The average translational kinetic energy per molecule in container B is
twice that for container A
the same as that for container A
half that for container A
impossible to determine.
Two containers hold an ideal gas at the same temperature and pressure. Both containers hold the same type of gas but container B has twice the volume of container A. The internal energy of the gas in container B is
impossible to determine
Two containers hold an ideal gas at the same temperature and pressure. Both containers hold the same type of gas but container B has twice the volume of container A. The rms speed of the gas molecules in container B is
How does the internal energy of an ideal gas change as it follows path i->f in figure?
Eint increases
Eint decreases
Eint stays the same
There is not enough information to determine how Eint changes
How does the internal energy of an ideal gas as it follows path f->f1 along the isotherm labeled T + deltaT in figure ?
increases
decreases
stays the same
There is not enough information to determine how changes
Latent heat is
the heat released or absorbed by a thermodynamic system during a process that occurs without a change in temperature
the amount of energy needed to raise the temperature of sample by 1°C
the heat capacity per unit mass
the amount of heat required to change a unit mass of a substance by one degree in temperature
amount of energy necessary to raise the temperature of 1 g of water from 14.5°C to 15.5°C.
Adiabatic process is
process that occurs at constant volume
process that occurs at constant temperature
process that occurs at constant pressure
process in which the net heat transfer between the system and its surroundings is zero
process that obeys the relation: pVn=C
A diatomic gas molecule has ... degrees of freedom
3
5
6
7
more
Energy may be transferred by
work
conduction
convection
radiation
all answers are correct
The molar specific heat of a gas is measured at constant volume and found to be 11R/2. The gas is most likely to be
monatomic
diatomic
monatomic or diatomic, depends on the conditions
polyatomic
all answers are incorrect
Parallel wires carrying currents I1 and I2 respectively
repel if they are directed opposite
will attract if they are directed opposite
will not interact
What are the opposite ends of a magnet called?
Its terminals
Its north and south poles
Its magnetic fields
Its electromagnetic poles
How are electrical charges and magnetic poles similar?
Unlike attract and the same type repel
Both are plus and minus
Magnetic poles attract electrons
Both change positive to negative charges
How can you show that electricity creates a magnetic field?
Use a compass near a wire with current flowing through it
Only magnets create magnetic fields
Move a wire through a magnetic field
Connect a battery to the magnetic field
How can you make an electromagnet?
Attach a natural magnet to a battery
Run current through a wire wrapped around an iron rod
Line up the N and S poles of a magnet with an electric wire
Wrap a magnet around a piece of wire with current flowing through it
What happens when you turn off the current in an electromagnet?
The magnetism is turned off
The current keeps flowing because of the magnetic force
The electromagnet reverses its polarity
The electromagnet becomes a generator
How can you create electricity with a magnet?
Attach a magnet to a battery
By putting a current through a wire around a magnet
By moving a wire through a magnetic field
You can't, because only friction on electric charges creates electricity
Can you create electricity with a magnet?
No, because only friction on electric charges or batteries create electricity
Yes, by moving a wire through a magnetic field
Yes, by putting a current through a wire around a magnet
Yes because magnets use electricity to stay effective
The geomagnetic field
makes the Earth like a huge horseshoe magnet
runs exactly through the geographic poles
makes a compass work
makes an electromagnet work
A material that can be permanently magnetized is generally said to be
magnetic
electromagnetic
permanently magnetic
ferromagnetic
The magnetic flux around a straight current-carrying wire
gets stronger with increasing distance from the wire
is strongest near the wire
does not vary in strength with distance from the wire
consists of straight lines parallel to the wire
The gauss is a unit of
overall magnetic field strength
ampere-turns
magnetic flux density
magnetic power
If a wire coil has 10 turns and carries 500 mA of current, what is the magnetomotive force in ampere-turns?
5,000
50
5.0
0.02
Which of the following is not generally observed in a geomagnetic storm?
Charged particles streaming out from the Sun
Fluctuations in the Earth’s magnetic field
Disruption of electrical power transmission
Disruption of microwave propagation
A device that reverses magnetic field polarity to keep a dc motor rotating is
a solenoid
an armature coil
a commutator
a field coil
When the speed at which a conductor is moved through a magnetic field is increased, the induced voltage
remains constant
reaches zero
The induced voltage across a coil with 250 turns that is located in a magnetic field that is changing at a rate of 8 Wb/s is
1,000 V
2,000 V
31.25 V
3.125 V
For a given wirewound core, an increase in current through the coil
reverses the flux lines
decreases the flux density
increases the flux density
causes no change in flux density
If the cross-sectional area of a magnetic field increases, but the flux remains the same, the flux density
Increases
remains the same
doubles
When the current through the coil of an electromagnet reverses,
direction of the magnetic field reverses
direction of the magnetic field remains unchanged
magnetic field expands
magnetic field collapses
What is the reluctance of a material that has a length of 0.07 m, a cross-sectional area of 0.014 m2, and a permeability of 4,500 Wb/At × m?
1111 At/Wb
111 At/Wb
11 At/Wb
1 At/Wb
A coil of wire is placed in a changing magnetic field. If the number of turns in the coil is decreased, the voltage induced across the coil will
increase
decrease
remain constant
be excessive
What is the flux density when the flux is 5.5 Wb and the cross-sectional area is 6 × 10–3 m2?
91.7 µT
917 µT
91 T
9.7 T
If the steel disk in a crankshaft position sensor has stopped with the tab in the magnet's air gap, the induced voltage
is zero
will remain constant
What is the flux density in a magnetic field in which the flux in 0.1 m2 is 600 Wb?
6,000 µT
600 µT
600 T
6 T
A parallel-plate capacitor with air between the plates has an area A=2.00·104 m2 and a plate separation d=1.00 mm. Find its capacitance.
C=1.77 pF
C=1.77 F
C=1.77 mF
C=1.77 nF
Find the equivalent capacitance between a and b for the combination of capacitors shown in Figure. All capacitances are in microfarads.
6.0 μF
6.0 F
5.0 μF
6.0 nF
A parallel-plate capacitor has plates of dimensions 2.0 cm by 3.0 cm separated by a 1.0-mm thickness of paper. Find its capacitance (k = 3.7, ε0=8.85·10-12 C2/N·m2).
20 pF
20 F
40 pF
60 pF
Find the electric flux Φe though the spherical surface, covers the point-like charges q1=5 nC and q2=-2 nC. (ε0=8.85·10-12 C2/N·m2)
Φe=339 N·m2/C
Φe=0.339 N·m2/C
Φe=339 N/C
Φe=339 N·m2
Find the attractive force F between nuclei of hydrogen atom and electron. Radius of hydrogen atom is r=0.5·10-10 m; modules charge of nuclei are equal and opposite to charge sign of electron (ε0=8.85·10-12 C2/N·m2).
F=92.3·10-9 N
F=92.3 N
F=92.3·10-9 N/m2
F=923·10-9 N
Two point-like charges in air (ε=1) at the distance r1=20 sm from each other interact with some force. At what distance r2 one needs to place this charges in oil (ε2=5) to get the same force of interaction?
r2=8.94 sm
r2=8.94 m
r2=8.94·103 m
r2=8.94·10-3 m
The electron and proton of a hydrogen atom are separated (on the average) by a distance of approximately 5.3·10-11 m. Find the magnitudes of the electric force between the two particles. (ke=8.99·109 N·m2/C2)
8.2·10-8 N
8.2 N
8.2·10-9 N
8.2·109 N
Calculate the resistance of an aluminum cylinder that has a length of 10.0 cm and a cross-sectional area of 2.00·10-4 m2 (ρ=2.82·10-8 Ω·m).
R=1.4·10-5 Ω
R=1.4·10-3 Ω
R=1.4 Ω
R=1.4·105 Ω
Calculate the resistance of an glass cylinder that has a length of 10.0 cm and a cross-sectional area of 2.00·10-4 m2 (ρ=3·1010 Ω·m).
R=1.5·10^13 Ω
R=1.5·10^-13 Ω
R=1.5·10^3 Ω
Calculate the resistance per unit length of a 22-gauge Nichrome wire, which has a radius of 0.321 mm (The resistivity of Nichrome is 1.5·10-6 Ω·m).
4.6 Ω/m
4.6 Ω
4.6 Ω·m
4.6·10-3 Ω/m
If a potential difference of 10 V is maintained across a 1.0-m length of the Nichrome wire with resistance 4.6 Ω, what is the current in the wire?
2.2 A
0.46 A
2.2·10-3 A
0.46·103 A
An electric heater is constructed by applying a potential difference of 120 V to a Nichrome wire that has a total resistance of 8.00 Ω. Find the current carried by the wire.
15 A
0.06 A
15·10-3 A
0.06·10-3 A
An electric heater is constructed by applying a potential difference of 120 V to a Nichrome wire that has a total resistance of 8.00 Ω. Find the power rating of the heater.
1.8 kW
1.8 W
120 W
0.1 kW
A battery has an emf of 12.0 V and an internal resistance of 0.05 Ω. Its terminals are connected to a load resistance of 3.00 Ω. Find the terminal voltage of the battery.
11.8 V
8.07 V
11.95 A
Calculate the power delivered to the load resistor, if the current in the circuit is 3.93 A, the load resistance is 3.00 Ω.
46.3 W
11.79 W
35.37 W
Calculate the power delivered to the internal resistance of the battery, if the current in the circuit is 3.93 A, the internal resistance of 0.05 Ω.
0.772 W
0.1965 W
0.01 W
Four resistors are connected as shown in Figure. Find the equivalent resistance between points a and b
12 Ω
2.7 Ω
5.37 Ω
Four resistors are connected as shown in Figure. Find the equivalent resistance between points b and c.
2 Ω
0.5 Ω
9 Ω
Four resistors are connected as shown in Figure. Find the equivalent resistance between points a and c.
14 Ω
2.5 Ω
4.7 Ω
3.2 Ω
Three resistors are connected in parallel as shown in Figure. A potential difference of 18.0 V is maintained between points a and b. Find the current I1.
I1=6.00 A
I1=3.00 A
I1=2.00 A
Three resistors are connected in parallel as shown in Figure. A potential difference of 18.0 V is maintained between points a and b. Find the current I2.
Three resistors are connected in parallel as shown in Figure. A potential difference of 18.0 V is maintained between points a and b. Find the current I3.
Three resistors are connected in parallel as shown in Figure. A potential difference of 18.0 V is maintained between points a and b. Calculate the power delivered to resistor R1.
P1=108 W
P1=54 W
P1=36 W
Three resistors are connected in parallel as shown in Figure. A potential difference of 18.0 V is maintained between points a and b. Calculate the equivalent resistance of the circuit.
Req=1.64 Ω
Req=0.61 Ω
Req=18 Ω
A single-loop circuit contains two resistors and two batteries, as shown in Figure. (Neglect the internal resistances of the batteries.) Find the current in the circuit.
I=-0.33 A
I=0.33 A
I=1 A
I=-3 A
Consider three point charges located at the corners of a right triangle as shown in Figure, where q1 = q3 = 5.0 μC, q2 =-2.0 μC, and a = 0.10 m. Find the resultant force exerted on q3
F3=(-1.1i+7.9j)N
F3=(7.9i-1.1j)N
F3=(1.1i-7.9j)N
F3=(1.1i+7.9j)N
An electric dipole is defined as a positive charge q and a negative charge -q separated by a distance 2a. For the dipole shown in Figure, find the electric field E at P due to the dipole, where P is a distance y » a from the origin.
E≈(k * 2qa)/y^3
E≈(k*2q)/a^3
E≈(k*2)/y^5
E≈2qa/y^3
A rod of length l has a uniform positive charge per unit length λ and a total charge Q. Calculate the electric field at a point P that is located along the long axis of the rod and a distance a from one end.
E=(k* Q)/(a(l+a))
E=(k*Q)/(l+a)
E=(k*Q)/al
E=k/(a(l+a))
Calculate the ratio of the electrostatic to gravitational interaction forces between two electrons, between two protons. At what value of the specific charge q/m of a particle would these forces become equal (in their absolute values) in the case of interaction of identical particles? (γ=6.67·10-11 m3/(kg·s2), me=9·10-31kg, mp=1·10-27kg, ke=8.99·109 N·m2/ C2)
4·1042 (for electrons); 1·1036 (for proton); q/m=0.86·10-10 C/kg
4·1042 (for proton); 1·1036 (for electrons); q/m=0.86·10-10 C/kg
4·1045 (for proton); 1·1038 (for electrons); q/m=0.86·10-13 C/kg
4·1043 (for electrons); 1·1035 (for proton); q/m=0.86·10-11 C/kg
Find the currents I1, I2, and I3 in the circuit shown in Figure.
I1=2 A, I2=-3 A, I3=-1 A
I1=-2 A, I2=3 A, I3=1 A
I1=2 A, I2=-3 A, I3=-5 A
I1=3 A, I2=2 A, I3=1 A
The water (H2O) molecule has an electric dipole moment of 6.3·10-30 C·m. A sample contains 1021 water molecules, with the dipole moments all oriented in the direction of an electric field of magnitude 2.5·105 N/C. How much work is required to rotate the dipoles from this orientation (θ=0°) to one in which all the moments are perpendicular to the field (θ=90°)?
1.6·10-24 J
1.6·10-3 J
-1.6·10-3 J
1.6·10-25 J
A ball is thrown upward. While the ball is in free fall, does its acceleration
Decreases
Increases and then decreases
Decreases and then increases
Remain constant
After a ball is thrown upward and is in the air, its speed in all path
Remain the same
If vector B is added to vector A, which two of the following choices must be true in order for the resultant vector to be equal to zero?
A and B are parallel in the same direction and have same magnitude
A and B are parallel in opposite directions, but have same magnitude
A and B have the same magnitude
A and B are perpendicular but have same magnitude
None of them is right
A car moves along y-axes. In the figure, velocity of the car as a function of time is shown in three parts (I, II, III). Which statement is ALWAYS true?
Velocity is constant in part II
A car drives backward in part I
Velocity is negative in part III
Velocity is negative in part I
What is the cross product of two vectors A and B, if the angle between them is 30 degree, and magnitudes are |A|=4, |B|=2
5.6
4
0
8
2.5
When a box rests on the floor, it is acted upon by the gravitational and the _________________ force.
Centrifugal
Acceleration
Normal
Inertia
Friction
Motion is produced by
all forces
unbalanced forces
balanced forces
the absence of force
none of them
Force is that agent which produces or tends to produce the __________.
Speed in the body
Acceleration in the body
Constant velocity in the body
Constant angular velocity in the body
A force of 3N acts perpendicularly to a force of 4N. Their resultant has magnitude of ______
1N
5N
7N
9N
25N
In inelastic collision between the two bodies __________.
Only momentum of the system is conserved
Only the kinetic Energy of the system is conserved
Both the kinetic Energy and Momentum of the system remain the same
Total energy is not conserved
Work done by a grass cutter is maximum when he pulls it __________.
Making an angle 450 with the floor
Making an angle 900 with the floor
Along a line parallel to the floor
Making an angle 600 with the floor
A man does the work if he ___________.
Goes to fifth floor of the building
Goes to fifth floor of the building and comes back to ground floor
Remain on the ground floor
Goes to the basement and comes back to ground floor
In elastic collision between the two bodies __________.
When the force and displacement are parallel to each other, then work is __________.
Minimum
In rotational motion, the quantity, which plays the same role as the inertial mass in linear motion, is called ___________.
Angular momentum
Moment of inertia
Torque
Center of mass
Four identical particles, each with mass m, are arranged in the x, y plane as shown. They are connected by light sticks to form a rigid body. If m = 2.0 kg and a = 1.0 m, the rotational inertia of this array about the y-axis is:
4.0 kg m2
12 kg m2
9.6 kg m2
4.8 kg m2
none of these
Sound travels faster in
a vacuum
water
steel
air
Sound travels at about the same speed in all of the above media.
A woman sits on a spinning stool with her arms folded. When she extends her arms, which of the following occurs
She increases her moment of inertia, thus increasing her angular speed
She increases her moment of inertia, thus decreasing her angular speed.
She decreases her moment of inertia, thus increasing her angular speed
She decreases her moment of inertia, thus decreasing her angular speed
Her angular speed remains constant by conservation of angular momentum
The pressure at the surface of the ocean is 1 atm (1 x 105 Pa). At what approximate depth in the ocean water (ρ = 1025 kg/m3) would the absolute pressure be 2 atm?
1 m
5 m
10 m
100 m
1000 m
A plane loop of wire consisting for the bowling ball that rotates about z-axis?
+y
–y
+x
–x
+z
–z
A segment of steel railroad track has a length of 30.000 m when the temperature is 0.0°C. What is its length when the temperature is 40.0°C? (Average linear expansion coefficient for steel is α=11* 10-6 °C-1).
0.013 m.
30.013 m.
30.130 m.
30.003 m.
31.013 m.
An ideal gas occupies a volume of 100 cm3 at 20°C and 100 Pa. Find the number of moles of gas in the container (Universal gas constant R= 8.314 J/mol*K).
4.11 * 10-5 mol
20.11 * 10-6 mol
20.11 * 10-5 mol
1.20 * 10-6 mol
4.11 * 10-6 mol
The concrete sections of a certain superhighway are designed to have a length of 25.0 m. The sections are poured and cured at 10.0°C. What minimum spacing should the engineer leave between the sections to eliminate buckling if the concrete is to reach a temperature of 50.0°C? (Average linear expansion coefficient for concrete is α=12* 10-6 °C-1).
1.20 cm
1.25 cm
1.35 cm
25.20 cm
25.40 cm
Just 9.00 g of water is placed in a 2.00-L pressure cooker and heated to 500°C. What is the pressure inside the container? (Molar mass of water M(H2O) = 18 g/mol, universal gas constant R= 8.314 J/mol*K ).
16.1 Pa
1.61 Pa
1.61 MPa
161 MPa
161 Pa
The temperature of a silver bar rises by 10.0°C when it absorbs 1.23 J of energy by heat. The mass of the bar is 525 g. Determine the specific heat of silver.
128 J/kg . °C
234 J/kg . °C
380 J/kg . °C
860 J/kg . °C
2 010 J/kg . °C
A 50.0-g sample of copper is at 25.0°C. If 1 200 J of energy is added to it by heat, what is the final temperature of the copper? (Specific heat of copper c= 387 J/kg . °C).
50 °C
62 °C
77 °C
87°C
99 °C
Determine the work done on a fluid that expands from i to f as indicated in Figure.
12 MJ
-12 J
-12 MJ
-6 J
6 MJ
A gas is taken through the cyclic process described in Figure. Find the net energy transferred to the system by heat during one complete cycle.
12 kJ
12 J
1200 kJ
4 kJ
6 kJ
An ideal gas initially at 300 K undergoes an isobaric expansion at 2.50 kPa. If the volume increases from 1.00 m3 to and 12.5 kJ is transferred to the gas by heat, what is the change in its internal energy?
6.5 kJ
6.5 J
7.5 kJ
13.5 kJ
25 kJ
A glass window pane has an area of 3.00 m2 and a thickness of 0.600 cm. If the temperature difference between its faces is 25.0°C, what is the rate of energy transfer by conduction through the window? (Thermal conductivity of glass k= 0.8 W/m* °C)
10 W
100 W
100 kW
1 kW
10 kW
A cylinder contains a mixture of helium and argon gas in equilibrium at 150°C. What is the average kinetic energy for each type of gas molecule? (Boltzmann constant kB= 1.38* 10-23 J/K).
8.76* 10-23 J
8.76* 10-21 J
10.8* 10-21 J
10.8* 10-23 J
87.6* 10-21 J
Calculate the change in internal energy of 3.00 mol of helium gas when its temperature is increased by 2.00 K (Universal gas constant R= 8.314 J/mol*K ).
49.9 J
4.99 J
499 J
748 J
74.8 J
A 2.00-mol sample of a diatomic ideal gas expands slowly and adiabatically from a pressure of 5.00 atm and a volume of 12.0 L to a final volume of 30.0 L. What is the final pressure of the gas?
5.33 atm
4.21 atm
3.39 atm
2.91 atm
1.39 atm
A 2.00-mol sample of a diatomic ideal gas expands slowly and adiabatically from a pressure of 5.00 atm and a volume of 12.0 L to a final volume of 30.0 L. What are the initial and final temperatures? (Universal gas constant R= 8.314 J/mol*K, 1 atm= 1.013* 105 Pa )
365 K, 253 K
355 K, 243 K
345 K, 233 K
335 K, 223 K
325 K, 213 K
A 2.00-mol sample of a diatomic ideal gas expands slowly and adiabatically from a pressure of 5.00 atm and a volume of 12.0 L to a final volume of 30.0 L. Find Q, ΔEint, and W (Universal gas constant R= 8.314 J/mol*K).
0 J, -4.66 kJ, 4.66 kJ
0 J, 4.66 kJ, - 4.66 kJ
0 J, -4.66 kJ, - 4.66 kJ
0 J, 4.66 kJ, 4.66 kJ
0.66 J, -4.66 kJ, - 4.66 kJ
A heat engine takes in 360 J of energy from a hot reservoir and performs 25.0 J of work in each cycle. Find the efficiency of the engine.
6.94 %
14.4 %
23.25 %
45.2 %
100 %
A heat engine performs 200 J of work in each cycle and has an efficiency of 30.0%. For each cycle, how much energy is (a) taken in and (b) expelled by heat?
637 J, 437 J
647 J, 447 J
657 J, 457 J
667 J, 467 J
677 J, 477 J
A particular heat engine has a useful power output of 5.00 kW and an efficiency of 25.0%. The engine expels 8 000 J of exhaust energy in each cycle. Find the energy taken in during each cycle
10.7 kJ
11.7 kJ
12.7 kJ
13.7 kJ
14.7 kJ
The unit for permeability is
Wb/At × m
At/m
At/Wb
Wb
What is the magnetomotive force in a 75-turn coil of wire when there are 4 A of current through it?
18.75 At
30 At
300 At
187 At
The direction of a magnetic field within a magnet is
from south to north
from north to south
back to front
front to back
When the north poles of two bar magnets are brought close together, there will be
no force
a downward force
a force of attraction
a force of repulsion
The ability of a material to remain magnetized after removal of the magnetizing force is known as
permeability
reluctance
hysteresis
retentivity
The voltage induced across a certain coil is 200 mV. A 120 resistor is connected to the coil terminals. The induced current is
1.7 mA
16 mA
12 mA
120 mA
The induced voltage across a stationary conductor in a stationary magnetic field is
reversed in polarity
increased
decreased
When a solenoid is activated, the force that moves the plunger is
an electromagnetic field
a permanent magnetic field
varying voltage
a steady current
What is the magnetomotive force (mmf) of a wire with 8 turns carrying three amperes of current?
2,400 At
240 At
24 At
2.4 At
If a loop in a basic dc generator suddenly begins rotating at a faster speed, the induced voltage
remains unchanged
reverses polarity
If an electron moves perpendicular to the uniform magnetic field of magnitude 0.35 T with the speed equal to 4.69×106, what is the radius of its circular orbit? (me = 9.11×10-31kg)
7.63×104
7.63×10-5
7.63×106
0.73×10-6
Calculate the maximum kinetic energy of protons in a cyclotron of radius 0.50 m in a magnetic field of 0.35 T.
1.46 KeV
1.46 meV
1.46 MeV
0.146 eV
A rectangular copper strip 1.5 cm wide and 0.1 cm thick carries a current of 5 A. A 1.2 T magnetic field is applied perpendicular to the strip. Find the Hall voltage that should be produced.
0.442 µV
0.442 mV
4.42 V
44.2 V
A toroidal winding carrying a current of 5 A is wound with 300 turns/m of wire. The core is iron, which has a magnetic permeability of 5000µ0 under the given conditions. Find B inside the iron core.
9.43×〖10〗^(-3)T
9.43×〖10〗^(-2)T
0.943 T
9.43 T
Assume that a motor having coils with a resistance of 10 Ω is supplied by a voltage of 120 V. When the motor is running at its maximum speed, the back emf is 70V. Find the current in the coils when the motor is first turned on.
10 A
12 A
1 A
1.2 A
Assume that a motor having coils with a resistance of 10 Ω is supplied by a voltage of 120 V. When the motor is running at its maximum speed, the back emf is 70 V. Find the current in the coils when the motor has reached maximum speed.
3 A
4 A
5 A
6 A
Calculate the inductance of a solenoid containing 300 turns if the length of the solenoid is 25 cm and its cross-sectional area is 4 cm2.
0.181 mH
0.181 H
1.81 mH
1.81 H
Calculate the self-induced emf in the solenoid containing 300 turns if the length of the solenoid is 25 cm and the current through it is decreasing at the rate of 50 A/s.
0.905 mV
9.05 mV
0.905 V
9.05 V
Calculate the time constant of RL circuit consisting of a 30 mH inductor in series with 6 Ω resistor and 12 V battery.
180 ms
60 ms
5 ms
2 ms
Three identical capacitors connected in series. What single capacitance C is “equivalent” to this combination?
6C
3C
(1/6)C
(1/3)C
2C
You charge parallel-plate capacitor. When you pull the plates apart to a larger separation and battery remains connected to the capacitor
Remains the same
Alternates
Changes in an unpredictable way
The resonant angular frequency of series RLC circuit is
1/(LC)1/2
LC
(LC)2
(LC)1/2
1/(LC)
A wire of area 2 mm2 carries a current of 0.4mA. The average current density is
0.02A/m2
0.2 A/m2
2 A/m2
200 A/m2
20 A/m2
A square loop of side 0.1m carries 2A current. The magnetic dipole moment of the loop is
10-1 Am2
2*10-2 Am2
1 Am2
10 Am2
100 Am2
Current 0.5A flows in square wire loop of 10 cm side. What is magnetic dipole moment of the loop?
50 Am2
0.005 Am2
0.05 Am2
5 Am2
0.5 Am2
Of the three chief kinds of magnetic materials (diamagnetic, paramagnetic and ferromagnetic), which are used to make permanent magnets?
Only paramagnetic
All three
Paramagnetic and ferromagnetic
Only ferromagnetic
Only diamagnetic
In a photoelectric experiment at a frequency above cut off, the stopping potential is proportional to:
The energy of the most energetic electron before it is ejected
The energy of the least energetic electron before it is ejected
The energy of the most energetic electrons after it is ejected
The electron potential energy at the surface of the sample
The energy of the least energetic electron after it is ejected
What is the maximal number of electrons at shell with n=3
11
18
9
For the serial circuit work out the readings on the voltmeters V1 and V2 given the following values for R1=2Ohm and R2=10 Ohm, I1=1A, I2=1A
V1=1V; V2=5V;
V1=5V; V2=10V;
V1=4V; V2=1V;
V1=10V; V2=2V;
V1=2V; V2=10V;
What is a good insulator of electricity?
Silicon
Iron
Rubber
Steel
Salt water
Induction current opposes the reason causing it. It is the shortest formulation of
Einstein’s law
Lentz law
Biot-Savart law
Faraday’s law
Ampere’s law
Potential energy of current carrying loop with magnetic dipole moment µ=1Am2 in magnetic field B of 0.1T, when B and µ make angle 600 is
-0.05J
-1J
1J
0.5J
0J
Paramagnetism is closely associated with
The torque
The force exerted by electron dipole moments on each other
The tendency of electron dipole moments to align with an applied magnetic field
The exchange force between electrons
The tendency of electrons dipole moments to align opposite to an applied magnetic field
In an electromagnetic wave E0=3*106V/m. B0 equals
10T
10-2T
100T
1T
10-8T
What is an insulator of electricity?
A material that doesn’t allow the free electrons to easily travel through it.
A material that protects the free electrons from excess heat
A material that protects the free electrons from internal energy propagation
A material that allows the free ions to easily travel through it
A material that allows the free electrons to easily travel through it
Ohm’s law in differential form is
I={φ1-φ2±ε}/R
ω=γE2
I=V/R
I= ε/(R+r)
j=γE, where j is a current density, γ is a conductivity
The total number of electron states with n=3 and l=1 for an atom is:
Four
eight
two
ten
six
The thermal conductivity is the analog to:
Thermal expansion
Resistivity
Elasticity
Diffusivity
Viscosity
Resistance of metals in classical theory of electric conductivity is caused by
Collision of free electrons with dislocations or clasters
Collision of free electrons with impurity atoms in internodes
Collision of free electrons with each other
Collision of free electrons with vacancy defects
Collision of free electrons with ions of crystal structure
Which relation defines equipotential surface:
|E ⃗|=const
E ⃗(Δr) ⃗=const
E ⃗=const
φ=const
dφ/dz=const
Electric theory of dispersion was evaluated by:
Lorentz
Einstein
Minkovsky
Maxwell
Loop is uniformly rotating with angular velocity ω in uniform magnetic field. Loop has N coils and area of the loop is S. Rotating axis lies on loop’s plane and perpendicular to induction. What is the maximal EMF appeared in the loop:
NBS/2
NBS
NBS cos(ωt)
NBSω/2
NBSω
Current I=1A goes through the inductance with inductivity L=10-3H. What is the magnetic flux through inductance:
2·10-10Wb
2·10-3Wb
4π·10-10Wb
0.5·10-3Wb
10-3Wb
A toaster is rated at 600W when connected to a 120V source. What current does the toaster carry?
2A
1A
3A
4A
5A
Charge carries in metals are
electrons and holes
only electrons
only holes
positive ions
negative ions
An electrton traveling with speed v around a circle of radius r is equivalent to a current of:
evr/2
ev/r
2πer/v
2πev/r
ev/2πr
The emf inducted in an isolated circuit when the current in the circuit is changing by 10 A/s is 0.3 V. What is the self-inductance?
3 mH
3 µH
30 µH
30 mH
30 H
The magnetic field for a given electromagnetic wave has Bmax = 10-6T. Emax equals
3*102 V/m
10-8 V/m
5 V/m
3 V/m
100 V/m
An electromagnetic field propagates in +x direction. The electric field at a point in space is momentarily oriented in –z direction. The magnetic field at that point is momentarily oriented in
–y direction
+y direction
+z direction
+x direction
-x direction
In RLC circuit angular frequency of AC source rises. Inductive reactance
Oscillates about certain value
Magnetic flux through closed conducting loop changed from 10Wb to 5Wb in 10ms. The average EMF induced in the loop is
50V
500V
-5V
-500V
The magnitude of emf induced in an isolated circuit when the current in the circuit is changing by -10A/s is 0.2 V. What is the self-inductance?
2µH
20mH
20µH
20H
2mH
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