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PHSC1100 Dr. Tavossi's Class. Fall 2014.

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Physical Science Final Exam

Questão 1 de 128

1

The International System of Units, SI Units, or metrics units of: length, mass, and time are:

Selecione uma das seguintes:

  • m, kg, min

  • m, kg, h

  • ft, slug, s

  • m, kg, s

  • cm, g, s

Explicação

Questão 2 de 128

1

The power in SI-Unit is measured in Watt, that is related to energy by being equal to

Selecione uma das seguintes:

  • energy times time

  • energy consumed

  • energy wasted

  • energy times distance

  • energy per unit time

Explicação

Questão 3 de 128

1

The energy source most used in the United States is

Selecione uma das seguintes:

  • coal

  • water

  • natural gas

  • oil

  • biomass (wood)

Explicação

Questão 4 de 128

1

The two factors that influence energy consumption are:

Selecione uma das seguintes:

  • supply and demand

  • resource and price

  • cost and production

  • lifestyle and efficiency

Explicação

Questão 5 de 128

1

If you started with a $1,600 investment and you had $12,800 after 6 years, what would be the annual interest rate you received?

Selecione uma das seguintes:

  • 14%

  • 15%

  • 35%

  • 19%

Explicação

Questão 6 de 128

1

What is the amount of power in kilowatts consumed per capita in the United States?

Selecione uma das seguintes:

  • 2 kW

  • 3 kW

  • 12 kW

  • 5 kW

Explicação

Questão 7 de 128

1

Running a clothes dryer for 90 minutes (1.5 hours) at 1600 Watts will cost about ____ cents if the cost of electricity is 10 cents per kWh:

Selecione uma das seguintes:

  • 4 cents

  • 10 cents

  • 50 cents

  • 24 cents

Explicação

Questão 8 de 128

1

The growth rate of GDP of a certain country is 3.5% per year. This means that the GDP is doubling every ____

Selecione uma das seguintes:

  • 2 years

  • 10 years

  • 5 years

  • 20 years

Explicação

Questão 9 de 128

1

A simple machine, such as a set of pulleys and ropes, known as block and tackle, are devices or tools that multiply applied-force, and changes its direction, at the expense of:

Selecione uma das seguintes:

  • speed

  • velocity

  • distance

  • acceleration

Explicação

Questão 10 de 128

1

The following statement is describing which of the three Newton's Laws of Motion? When no-net force is acting is acting on an object, if it is at rest it remains at rest, or if it is in motion, it can only move at a constant velocity.

Selecione uma das seguintes:

  • First law

  • Second law

  • Third law

  • Law of gravity

Explicação

Questão 11 de 128

1

According to Newton's second law of motion, when a net-force acts on an object, the object must be ____

Selecione uma das seguintes:

  • accelerating

  • going at a constant speed

  • moving at constant velocity

  • at rest

Explicação

Questão 12 de 128

1

According to Newtons third law, if the push that the car tires give to the road-surface is the action force, the the reaction force is

Selecione uma das seguintes:

  • the weight of the car

  • the force of the car upon the tires

  • the friction force of the road-surface on the tires

  • the acceleration of the car

Explicação

Questão 13 de 128

1

If a 60 kg person is observed to accelerate at the rate of 4 m/s(^2), the net force responsible for this is

Selecione uma das seguintes:

  • 240 N

  • 100 N

  • 120 N

  • 140 N

Explicação

Questão 14 de 128

1

A car having an initial speed of 9 m/s starts to accelerate at the rate of 4 m/s(^2), the final speed after 5.5 seconds is

Selecione uma das seguintes:

  • 25 m/s

  • 15 m/s

  • 19 m/s

  • 31 m/s

Explicação

Questão 15 de 128

1

A car is moving at 22 m/s (50 mph), when driver sees the traffic light turning red and immediately applies the brakes, decelerating at 6 m/s(^2). What is the car's stopping distance, neglecting the driver's reaction times?

Selecione uma das seguintes:

  • 30.4 m

  • 10.2 m

  • 20.3 m

  • 40.3 m

Explicação

Questão 16 de 128

1

If a stone is dropped from a bridge that is 133 m above the water, how long will it take until the stone hits the water?

Selecione uma das seguintes:

  • 1.7 s

  • 5.2 s

  • 3.1 s

  • 6.2 s

Explicação

Questão 17 de 128

1

A ball is projected straight downward with an initial speed of 20 m/s. After 3 seconds, about how fast is it going?

Selecione uma das seguintes:

  • 30 m/s

  • 45.4 m/s

  • 49.4 m/s

  • 60.5 m/s

Explicação

Questão 18 de 128

1

A ball is projected straight up at an initial speed of 24.5 m/s. After 2.5 seconds, what is it's speed?

Selecione uma das seguintes:

  • 9.8 m/s

  • 14.7 m/s

  • 4.9 m/s

  • 0 m/s

Explicação

Questão 19 de 128

1

How much work is required to increase the velocity of a 4 kg car from rest to 5 m/s?

Selecione uma das seguintes:

  • 100 J

  • 200 J

  • 20 J

  • 50 J

Explicação

Questão 20 de 128

1

The gravitational potential energy of an object, near the Earth's surface, and the work done to lift the object to the height "h" is given by

Selecione uma das seguintes:

  • weight times height

  • mass times height

  • mass times speed

  • mass times acceleration

Explicação

Questão 21 de 128

1

From work-KE theorem, what is the speed of a car of mass 2500 kg, after it is pushed by a force of 500 N over a horizontal distance of 10 m?

Selecione uma das seguintes:

  • 1 m/s

  • 4 m/s

  • 2 m/s

  • 3 m/s

Explicação

Questão 22 de 128

1

When a car is braked to a stop, it's kinetic energy is transformed into

Selecione uma das seguintes:

  • stopping energy

  • energy of motion

  • potential energy

  • heat energy

Explicação

Questão 23 de 128

1

Our nose cracker moved back and forth as shown. The kinetic energy will be greatest at what point?
(A -> B -> C)

Selecione uma das seguintes:

  • A

  • B

  • A and C

  • halfway between A and B

Explicação

Questão 24 de 128

1

The efficiency of a lightbulb is the ratio of the

Selecione uma das seguintes:

  • energy input to the energy out of the bulb

  • light output of the bulb to the electrical energy input

  • heat energy out to the electrical energy in

  • voltage output of the bulb to the power input

Explicação

Questão 25 de 128

1

If the energy conversion efficiencies in a 3 step process are 36% for the first step, 44% for the second, and 26% for the third, the overall efficiency is about:

Selecione uma das seguintes:

  • 4%

  • 9%

  • 0.4%

  • 2%

Explicação

Questão 26 de 128

1

For a fossil fueled electrical generating plant, 10,000 Btus of chemical energy input into the plant will result in about how many Btus of waste heat dumped into the environment if the efficiency of power plant is 35%?

Selecione uma das seguintes:

  • 8,800 Btus

  • 10,000 Btus

  • 4,080 Btus

  • 6,500 Btus

Explicação

Questão 27 de 128

1

The first law of thermodynamics states that: heat added to the system, plus work done on the system, equals change in the total energy of the system. This statement is based on-

Selecione uma das seguintes:

  • how heat can be conducted

  • how temperature is increased

  • the principle of conservation of energy

  • the state of the system

Explicação

Questão 28 de 128

1

The second law of thermodynamics states that heat energy flows in the direction of

Selecione uma das seguintes:

  • up, since heat rises

  • higher temperature

  • lower temperature

  • lower entropy

Explicação

Questão 29 de 128

1

The total R-value of a wall made of different layers of materials is obtained by

Selecione uma das seguintes:

  • multiplying the R values of each layer

  • the sum of R values for each layer

  • sum of areas of each layer

  • sum of thicknesses of each layer

Explicação

Questão 30 de 128

1

When ice crystals form in the clouds,

Selecione uma das seguintes:

  • phase change from solid to liquid occurs

  • the thermal mass of the atmosphere increases

  • heat energy is released

  • the atmosphere becomes colder

Explicação

Questão 31 de 128

1

The R-value of material is not related to its

Selecione uma das seguintes:

  • composition

  • area

  • thickness

  • resistance to heat flow

Explicação

Questão 32 de 128

1

An object with a very high specific heat will

Selecione uma das seguintes:

  • decrease in temperature very fast if removed from the source

  • lose its heat very fast

  • always be water

  • take considerably more heat to raise its temperature

Explicação

Questão 33 de 128

1

The efficiency of an electric motor is the ratio of the

Selecione uma das seguintes:

  • energy into the motor to the energy out of it

  • heat released to rotational energy

  • heat plus electricity produced to the electrical input

  • shaft work output to the electrical energy input

Explicação

Questão 34 de 128

1

For a furnace to provide 80,000 Btu/h of thermal energy to a living space, what should the rate of heat supplied by the fuel be if the furnace efficiency is 65%?

Selecione uma das seguintes:

  • 103,000 Btu

  • 15,300 Btu

  • 123,000 Btu

  • 223,000 Btu

Explicação

Questão 35 de 128

1

A heat engine ____

Selecione uma das seguintes:

  • converts work into heat energy

  • can be 100% efficient in the absence of friction

  • can have no cold sink

  • needs a hot source and a cold sink to be able to work

Explicação

Questão 36 de 128

1

The heat transfer by conduction through an area 10ft x 7ft section of the wall, with R-value of 35 (ft^2-F-h/Btu), with temperature difference between the sides change in temperature equaling 10 degrees farenheit, will be

Selecione uma das seguintes:

  • 10 Btu/h

  • 35 Btu/h

  • 15 Btu/h

  • 20 Btu/h

Explicação

Questão 37 de 128

1

Since the rate of heat transfer by conduction is proportion to the change in temperature, what percent savings in your cooling bill would you expect if you turned the thermostat up from 70 degrees to 74 degrees, and the outside temperature is 95 degrees?

Selecione uma das seguintes:

  • 26%

  • 46%

  • 6%

  • 16%

Explicação

Questão 38 de 128

1

Thermal radiations are electromagnetic waves and like all EM waves are of the type

Selecione uma das seguintes:

  • transverse waves

  • longitudinal waves

  • surface waves

  • torsional waves

Explicação

Questão 39 de 128

1

Normally the phase changes from vapor to liquid to solid takes place in that order when the heat is

Selecione uma das seguintes:

  • kept constant

  • pressure is reduced

  • added

  • removed

Explicação

Questão 40 de 128

1

85 degrees Fahrenheit is equal to ____ temperature in Kelvin scale

Selecione uma das seguintes:

  • 286 K

  • 308 K

  • 316 K

  • 302 K

Explicação

Questão 41 de 128

1

The Carnot efficiency (maximum possible efficiency) of a heat engine operating between 20 degrees C and 2000 degrees C will be about ____. (Note: the temperature must be in Kelvins -> C + 273)

Selecione uma das seguintes:

  • 35%

  • 100%

  • 72%

  • 87%

Explicação

Questão 42 de 128

1

A heat pump will have an efficiency of about ____

Selecione uma das seguintes:

  • 35%

  • 100%

  • 200%

  • 50%

Explicação

Questão 43 de 128

1

What are the percentages of Infra-Red (IR), Ultra Violet (UV), and Visible Light in the solar radiation at the top of the Earth's atmosphere?

Selecione uma das seguintes:

  • 17% IR, 37% UV, 46% visible

  • 37% IR, 5% UV, 58% visible

  • 51% IR, 12% UV, 37% visible

  • 47% IR, 7% UV, 46% visible

Explicação

Questão 44 de 128

1

The amount of infrared radiation emitted, or absorbed, by an object, apart from the temperature difference with the surroundings, and the surface area, depends also on

Selecione uma das seguintes:

  • shape

  • color, surface texture

  • its type of material

  • density

Explicação

Questão 45 de 128

1

What is the wavelength of the electromagnetic waves emitted by a Satellite-TV, that has typically a frequency of 12 GHz? (GHz= 10^9 Hz)

Selecione uma das seguintes:

  • 0.015 m

  • 0.025 m

  • 0.035 m

  • 0.013 m

Explicação

Questão 46 de 128

1

Specific heat of a substance is defined as the

Selecione uma das seguintes:

  • heat required to increase its temper by one-degree Fahrenheit

  • heat required to increase its temperature by one-degree Celsius

  • heat required to increase its heat by one joule

  • heat required to increase the temperature one one unite mass by one degree

Explicação

Questão 47 de 128

1

How much heat energy is required to increase the temperature of 3 kg of water from room temperature of 20 degrees C to the boiling point 100 degrees C? (Specific heat of water in SI units is C= 4186 J/kg*C)

Selecione uma das seguintes:

  • 20.4 kJ

  • 50.6 kJ

  • 100.5 kJ

  • 789.7 kJ

Explicação

Questão 48 de 128

1

What produces the cooling in a refrigerator?

Selecione uma das seguintes:

  • evaporation of Freon outside

  • compression on Freon inside

  • condensation of Freon

  • evaporation of Freon inside

Explicação

Questão 49 de 128

1

The geothermal heat, that is, the heat from the interior of the earth, can be used to warm or cool a house

Selecione uma das seguintes:

  • in a certain area

  • near hot water springs

  • eight feet below the ground everywhere

  • more than 100 feet underground

Explicação

Questão 50 de 128

1

A wall of a typical house is made of six layers with R-values given in (ft^2- F - h/Btu); from interior dead air later (R1= 0.68), 0.5 in sheetrock (R2= 0.45), 5.5 in fiberglass insulation (R3= 19), 0.5 in plywood (R4= 0.63), exterior dead air layer (R5 = 0.68). If temperature difference between outside and inside is 22 degrees F, and the total area of the wall is 360 ft^2 the rate of heat transfer by conduction is ____.

Selecione uma das seguintes:

  • 567.4 Btu/h

  • 156.3 Btu/h

  • 369.4 Btu/h

  • 423.6 Btu/h

Explicação

Questão 51 de 128

1

The Carnot efficiency of a heat engine operating between 21 degrees C and 1200 degrees C will be about

Selecione uma das seguintes:

  • 52%

  • 78%

  • 80%

  • 90%

Explicação

Questão 52 de 128

1

Amount of heat and temperature of an object are different because amount of heat depends on the

Selecione uma das seguintes:

  • temperature difference

  • energy of its molecules

  • size of its molecules

  • amount of substance

Explicação

Questão 53 de 128

1

The first law of thermodynamics is related to the

Selecione uma das seguintes:

  • conservation of energy

  • heat and temperature

  • entropy and temperature

  • heat and work

Explicação

Questão 54 de 128

1

To keep an iced drink cold for the longest time, what color cup would you use?

Selecione uma das seguintes:

  • red

  • blue

  • white

  • black

Explicação

Questão 55 de 128

1

Suppose it takes 48,000 Btu to heat up the water in a tank. If the heating element has an output of 2,800 W, then how long will it take to heat up the water, assuming no extra heat losses?

Selecione uma das seguintes:

  • 2 h

  • 5 h

  • 30 mins

  • 3 h

Explicação

Questão 56 de 128

1

The existence of the four seasons, in the mid-latitude locations, is due to the

Selecione uma das seguintes:

  • moon-earth interaction

  • variation of the sun-earth distance

  • tilt of rotation axis of the earth by 23.5 degrees

  • variation of the moon-earth distance

Explicação

Questão 57 de 128

1

Heat transfers by all three ways; conduction, convection, and radiation; are directly proportional to the....

Selecione uma das seguintes:

  • surface temperature

  • surface roughness

  • surface color

  • surface area

Explicação

Questão 58 de 128

1

The optimal angle of tilt, from the horizontal, for a south facing flat-plate solar collector, or photovoltaic cells panel, in a location with the latitude of 50.5 degrees N, for the purpose of solar panels installation is

Selecione uma das seguintes:

  • 50.5 degrees

  • 60.5 degrees

  • 20.5 degrees

  • 30.5 degrees

Explicação

Questão 59 de 128

1

What is the main advantage of using thermal mass, in the form of thick concrete floor, or Trombe wall, in a direct-gain passive solar system?

Selecione uma das seguintes:

  • to increase temperature fluctuations during the night

  • to provide foundation support for the collector superstructure

  • to increase the insolation on south-facing windows

  • to reduce temperature fluctuations during the day

Explicação

Questão 60 de 128

1

During what season will more insolation be delivered to a vertical south-facing window on a clear day?

Selecione uma das seguintes:

  • fall

  • winter

  • spring

  • summer

Explicação

Questão 61 de 128

1

The insolation in a certain location is 900 W/m^2 and 85% of this is direct component on the collector. If a useful rate of energy needed for cooking is 150 W, then what area of the solar collector oven in the form of parabolic mirror is needed to intercept this amount of radiation, take the efficiency to 20%?

Selecione uma das seguintes:

  • 0.98 m^2

  • 1.2 m^2

  • 1.6 m^2

  • 0.87 m^2

Explicação

Questão 62 de 128

1

Determine the collector area needed to heat 554 lbs of water (80 gallons), in one day, from 50 degrees F to 130 degrees F, if the insolation is 1700 Btu/d/ft^2 and the FPC efficiency is 48%.

Selecione uma das seguintes:

  • 54 ft^2

  • 62 ft^2

  • 73 ft^2

  • 33 ft^2

Explicação

Questão 63 de 128

1

The main difference between transverse and longitudinal waves is that transverse waves

Selecione uma das seguintes:

  • travel faster than longitudinal waves

  • are not shear waves

  • can not be polarized

  • can be polarized

Explicação

Questão 64 de 128

1

A typical microwave generates the electromagnetic waves of frequency 2.45 GHz (1 Giga= 10^9). The wavelength of the radio wave corresponding to the frequency is

Selecione uma das seguintes:

  • 9.26 cm

  • 8.48 cm

  • 11.45 cm

  • 12.24 cm

Explicação

Questão 65 de 128

1

In prospection for ore by gravimetric method, (to measure the variation of g=9.8 m/s^2 on the earths surface at a fixed height) how do you distinguish between petroleum and ore?

Selecione uma das seguintes:

  • g would be greater over an ore deposit than a petroleum deposit

  • density of ore is less than petroleum

  • g does not change over the surface of the earth

  • g would be greater over a petroleum deposit than an ore deposit

Explicação

Questão 66 de 128

1

When seismic waves (or light waves) travel from one medium into another medium with different wave-speed, what is the difference between reflection and refraction, at the interface between the two media?

Selecione uma das seguintes:

  • Refracted wave bends and goes through the second medium

  • reflection and refraction are the same effect

  • reflection can only occur on a smooth interface

  • refraction will not bend the direction of the waves

Explicação

Questão 67 de 128

1

What is the main difference between electromagnetic waves and sound waves?

Selecione uma das seguintes:

  • electromagnetic waves can travel in a vacuum

  • sound waves travel faster

  • sound waves can be polarized

  • sound waves can travel in a vacuum

Explicação

Questão 68 de 128

1

The magnitude of gravitational attraction between a 135 kg-person and a 290,000 kg-door of a bunker, with 0.2 m distance between their centers of mass is ____. (G= 6.674 x 10^-11 n*m2/kg2)

Selecione uma das seguintes:

  • 6.53 x 10^-2 N

  • 7.64 x 10^-3

  • 8.75 x 10^-3

  • 5.42 x 10^-2

Explicação

Questão 69 de 128

1

In a fractionating tower of an oil-refinery, where crude oil is heated from the bottom to separate different hydrocarbon constituents, what is the least volatile constituent of crude oil? That is, the component with the highest boiling point?

Selecione uma das seguintes:

  • industrial fuel oil

  • kerosene

  • gasoline

  • asphalt

Explicação

Questão 70 de 128

1

The longevity of a fossil-fuel reserve is determined by the ratio of

Selecione uma das seguintes:

  • proven reserves/ daily production production rate

  • proven reserves / yearly production rate

  • indicated reserves / yearly production rate

  • inferred reserves yearly production rate

Explicação

Questão 71 de 128

1

Pressure on a surface inside a fluid is due to the

Selecione uma das seguintes:

  • force of gravity

  • rotational energy of fluid molecules

  • surface tension

  • continuous knocking of fluid molecules on the surface

Explicação

Questão 72 de 128

1

Static pressure at a depth h below the surface of a fluid is given by

Selecione uma das seguintes:

  • mass x g x h

  • density x g x h

  • force x time x h

  • h x g x volume

Explicação

Questão 73 de 128

1

A swimming pool has a depth of 2.5 m. What is the gauge pressure at the bottom of this pool, in psi? (Density of water is pw= 1000 kg/m3)

Selecione uma das seguintes:

  • 3.553 psi

  • 4.652 psi

  • 7.324 psi

  • 1.334 psi

Explicação

Questão 74 de 128

1

The normal blood pressure is expressed as 80 to 120 mm-of-mercury, which are gauge pressure values. When these values are converted into psi they become ____

Selecione uma das seguintes:

  • 1.432, 2.133 psi

  • 1.547, 2.320 psi

  • 1.652, 2.358 psi

  • 1.321, 2.142 psi

Explicação

Questão 75 de 128

1

A balloon in the air is buoyed up by a force equal to the

Selecione uma das seguintes:

  • weight of the air it displaces

  • weight of the balloon and its contents

  • mass of air displace

  • density of the surrounding air

Explicação

Questão 76 de 128

1

What is the buoyant force on a 3 ton ship that is floating in the sea?

Selecione uma das seguintes:

  • 2.5 tons

  • 3.0 tons

  • 3.5 tons

  • 1.5 tons

Explicação

Questão 77 de 128

1

Why do you expect photochemical smog to be a greater problem in a city like Los Angeles than in a heavily industrialized city like Pittsburgh?

Selecione uma das seguintes:

  • LA has more automobile traffic

  • LA gets more days with temperature inversion

  • LA is less windy

  • Pittsburg has more desulfurization plants

Explicação

Questão 78 de 128

1

The acidity of rain, or other solutions, is measured by the pH number scale that varies from 0 to 14. What does a pH number represent?

Selecione uma das seguintes:

  • 10 to the positive power of the hydrogen ion concentration

  • the larger the pH number the stronger the acidity

  • the smaller the pH number the less acidic the solution is

  • 10 to the negative power of the hydrogen ion concentration in the solution

Explicação

Questão 79 de 128

1

The pressure exerted on your finger if you hold up a 15 lb box of apples, if the contact surface of your finger is 0.25 in x 0.25 in, would be ____

Selecione uma das seguintes:

  • 200 psi

  • 220 psi

  • 240 psi

  • 160 psi

Explicação

Questão 80 de 128

1

Suppose it takes 38,500 Btu to heat up water in a tank. If the heating element has an output power of 2,500 W, then how long would it take to heat up the water, assuming no extra heat losses? (1 Btu= 1055 Joules, 1 Watt = 1 Joule per second, 1 hour = 3600 s)

Selecione uma das seguintes:

  • 55 mins

  • 2.5 hours

  • 3.5 hours

  • 4.5 hours

Explicação

Questão 81 de 128

1

During which season will more insolation be delivered to a vertical south facing window on a clear day?

Selecione uma das seguintes:

  • Winter

  • Fall

  • Spring

  • Summer

Explicação

Questão 82 de 128

1

The optimum angle of tilt from the horizontal, for a flat plate solar collector, or panels of photovoltaic cells, both facing South, in a location with a latitude of 50.5 degrees North, for the purpose of solar panel installations is

Selecione uma das seguintes:

  • 30.5 degrees

  • 40.5 degrees

  • 50.5 degrees

  • 60.5 degrees

Explicação

Questão 83 de 128

1

The measure of the angle of position of the sun from the South direction is called the

Selecione uma das seguintes:

  • altitude

  • azimuth

  • declination

  • inclination

Explicação

Questão 84 de 128

1

If the insolation (I) upon a flat plate collector is 890 (Btu/ft2*day), how large must the area A of the collector be to provide (Q/t= 12,400 Btu/hr of thermal energy for one day (24 hours)? Take the collector efficiency to be 57.5% (Note: Btu/h is related to I A and E by Q/t = I*A*E)

Selecione uma das seguintes:

  • 18 ft2

  • 164 ft2

  • 376 ft2

  • 637 ft2

Explicação

Questão 85 de 128

1

The acidity of rain, or a solution, is measured by the pH number, that varies from 0 to 14, what does a pH number represent?

Selecione uma das seguintes:

  • 10 to the positive power represent the hydrogen ion concentration per mole

  • the larger the pH the stronger the acidity of the solution

  • 10 to the negative power of the hydrogen ion concentration per mole in the solution

  • the smaller the pH the less acidic the solution

Explicação

Questão 86 de 128

1

Pressure on a surface is defined as

Selecione uma das seguintes:

  • mass x speed

  • mass x velocity

  • density x volume

  • force per unit area

Explicação

Questão 87 de 128

1

Pressure on a surface inside a fluid is caused by

Selecione uma das seguintes:

  • weight of fluid molecules

  • force of gravity

  • potential energy of fluid molecules

  • repeated knocking of the fluid molecules on the surface

Explicação

Questão 88 de 128

1

Static pressure at a depth h in a fluid is given by

Selecione uma das seguintes:

  • h x g x volume

  • mass x g x h

  • force x time x h

  • density x g x h

Explicação

Questão 89 de 128

1

Atmospheric pressure, at sea level, is 14.7 psi, the gauge pressure of an automobile tire is 38 psi, the absolute pressure of this tire in Pascal is..... (Note: 1 psi = 6895 Pa)

Selecione uma das seguintes:

  • 131,100 Pa

  • 248,200 Pa

  • 353,300 Pa

  • 363,400 Pa

Explicação

Questão 90 de 128

1

A balloon in the air is buoyed up by a force equal to the ___

Selecione uma das seguintes:

  • density of the surrounding air

  • atmospheric pressure

  • weight of the balloon and its contents

  • weight of the air it displaces

Explicação

Questão 91 de 128

1

Which of the following air pollutants is emitted in about equal amounts by stationary and mobile sources?

Selecione uma das seguintes:

  • particulates

  • carbon monoxide

  • nitrogen oxides

  • sulfur dioxides

Explicação

Questão 92 de 128

1

Ozone layer in the stratosphere

Selecione uma das seguintes:

  • dissipates within days

  • combines with NO or NO2 to produce smog

  • absorbs infrared light from the sun

  • provides protection from incoming UV solar radiation

Explicação

Questão 93 de 128

1

How much has the global temperature on earth changed over the past 100 years?

Selecione uma das seguintes:

  • 0.5 degrees C

  • 1.0 degrees C

  • 1.5 degrees C

  • 2.0 degrees C

Explicação

Questão 94 de 128

1

One of the fundamentals of electrostatic is that the force between two unlike charges is

Selecione uma das seguintes:

  • repulsive

  • neutralized

  • attractive

  • zero

Explicação

Questão 95 de 128

1

Electricity is transmitted from plower plants at ____ to reduce by Joule heating in the transmission lines, which is about 10%.

Selecione uma das seguintes:

  • high currents

  • low resistance

  • high resistance

  • high voltage

Explicação

Questão 96 de 128

1

What quantity is the same for three resistors in a series circuit?

Selecione uma das seguintes:

  • power

  • resistance

  • current

  • voltage

Explicação

Questão 97 de 128

1

What quantity is the same for three resistors in a parallel circuit?

Selecione uma das seguintes:

  • power

  • resistance

  • current

  • voltage

Explicação

Questão 98 de 128

1

A circuit consists of one lightbulb of resistance of 144 ohms and another lightbulb of 240 ohms that are wired in series to a 120 V wall socket outlet. What is the current through this circuit?

Selecione uma das seguintes:

  • 0.10 A

  • 0.20 A

  • 0.30 A

  • 0.40 A

Explicação

Questão 99 de 128

1

Two resistors of 144 ohms and 240 ohms are wired in parallel to 120 V wall outlet socket outlet, the current through the 240 ohm resistor will be

Selecione uma das seguintes:

  • 0.3 A

  • 0.4 A

  • 0.5 A

  • 0.6 A

Explicação

Questão 100 de 128

1

The electrostatic force of attraction between two charges of q1= -35 x 10^-6 C and q2 = +69 x 10^-6 C, separated by a distance of 3 m is ___

Selecione uma das seguintes:

  • 0.4 N

  • 1.21 N

  • 2.41 N

  • 3.53 N

Explicação

Questão 101 de 128

1

A high temperature superconductor compounds such as YBCO ____

Selecione uma das seguintes:

  • provides large magnetic fields at room temperature

  • has no resistance at room temperature

  • has no electrical resistance below its critical temperature

  • generates constant voltage at low temperatures

Explicação

Questão 102 de 128

1

A lightbulb draws a current of 2.5 amps, when connected to a wall outlet of 120 V. What is the resistance of the bulb?

Selecione uma das seguintes:

  • 50 ohms

  • 100 ohms

  • 200 ohms

  • 300 ohms

Explicação

Questão 103 de 128

1

The resistance of four light bulbs are given below. Which one has the highest wattage?

Selecione uma das seguintes:

  • 144 ohms

  • 192 ohms

  • 240 ohms

  • 320 ohms

Explicação

Questão 104 de 128

1

How much current is drawn by 3240 W electrical appliance operating at 240 V?

Selecione uma das seguintes:

  • 11.3 A

  • 12.4 A

  • 13.5 A

  • 14.5 A

Explicação

Questão 105 de 128

1

What is the cost of running your water heater of power rating 2800 W for 2.5 hours per day, for one year or 365 days, if the electricity costs 12 cents per kWh?

Selecione uma das seguintes:

  • $95

  • $105

  • $206

  • $307

Explicação

Questão 106 de 128

1

The magnetic field of a bar magnet is similar to that produced by

Selecione uma das seguintes:

  • a horse shoe magnet

  • a straight current carrying wire

  • two coils separated by long distance

  • a current carrying solenoid

Explicação

Questão 107 de 128

1

Alternating current has an advantage over direct current because

Selecione uma das seguintes:

  • batteries can be displaced in most circuits

  • electrical generators can be made

  • produces no heat loss

  • one can step up, or down, the amount of voltage used

Explicação

Questão 108 de 128

1

A transformer (adaptor) can only operate if

Selecione uma das seguintes:

  • the power in equals the power out

  • an alternating current is used

  • the potential difference is large enough

  • we step down the current

Explicação

Questão 109 de 128

1

If the current through a 33 ohm resister and a 57 ohm resistor in series is 5 A, then the total voltage drop across both of these resistors will be

Selecione uma das seguintes:

  • 110 V

  • 120 V

  • 340 V

  • 450 V

Explicação

Questão 110 de 128

1

What transformer turns-ratio of secondary to primary is required to lower the voltage from 120 V wall socket outlet to 8 V for charging a cell phone?

Selecione uma das seguintes:

  • 15

  • 0.044

  • 0.075

  • 0.067

Explicação

Questão 111 de 128

1

A bird sitting on a bare high voltage wire is not electrocuted because ____

Selecione uma das seguintes:

  • of the high resistance of its body

  • its body is at a low electrical potential compared to the wire

  • the high voltage across its feet produced a small current

  • there is no electrical potential difference across its body because the other wire is out of reach

Explicação

Questão 112 de 128

1

For a photovoltaic cell of 0.5 V and of area 1 cm2, the maximum output power is 135 mW (mW= 10^-3 W). What is the current provided by this cell?

Selecione uma das seguintes:

  • 0.01 A

  • 0.02 A

  • 0.23 A

  • 0.27 A

Explicação

Questão 113 de 128

1

The site location for a wind turbine is especially important. If the power output goes as the cube of the wind velocity, then which of the following average velocities will give approximately 8 times as much output as 10 mph winds?

Selecione uma das seguintes:

  • 5 mph

  • 10 mph

  • 15 mph

  • 20 mph

Explicação

Questão 114 de 128

1

If the average wind speed for 24 hours is 16 mph at one site but 13 mph at another site for 12 hours and then 23 mph for 12 hours at another site, how much output can be expected from the first turbine compared to the turbine at the second site?

Selecione uma das seguintes:

  • 35%

  • 46%

  • 57%

  • 68%

Explicação

Questão 115 de 128

1

A 1000 MW power plant is shut down for one day (24 hours). What is the loss of income from this plant if the selling price were 10 cents/kWh (1 MW=10^6 kW).

Selecione uma das seguintes:

  • $180,000

  • $700,000

  • $2,400,000

  • $3,500,000

Explicação

Questão 116 de 128

1

For the following circuit, with all the bulbs identical, what is true for the brightness of the lights?
l -----------l (A)
l l_____
l (B) l l (C)
l _______ l ____ l

Selecione uma das seguintes:

  • A = B = C

  • A = 4B = 4C

  • A = .5B = .5C

  • A = B, C = 0

Explicação

Questão 117 de 128

1

The existence of atom was proposed by Democritus (420 BCE) and at the beginning of the 19th century, John Dolton proved that every element has an atom, by the ____

Selecione uma das seguintes:

  • law of electrostatics

  • ideal gas law

  • law of definite proportion

  • law of conservation of energy

Explicação

Questão 118 de 128

1

The discovery of atomic nucleus was made by firing fast moving ____ at a thin gold foil

Selecione uma das seguintes:

  • alpha particles

  • gamma rays

  • electrons

  • neutrons

Explicação

Questão 119 de 128

1

The isotopes of an element all have the same number of

Selecione uma das seguintes:

  • protons

  • electrons

  • positron neutrons

  • nucleons

Explicação

Questão 120 de 128

1

For the same energy, the most penetrating type of radiations are

Selecione uma das seguintes:

  • B-particles

  • X-rays

  • a-particles

  • y-rays

Explicação

Questão 121 de 128

1

The half-life of a radioactive nuclide is the time taken for _____

Selecione uma das seguintes:

  • half of its neutrons to decay

  • half of its electrons to decay

  • half of its mass to decay

  • half of its nuclei to decay

Explicação

Questão 122 de 128

1

At 9 am on Monday, a radioactive sample contained 80 million nuclei. At 9 am on Saturday, 2.5 million of these nuclei are left over and has not decayed. The half life of the sample is

Selecione uma das seguintes:

  • 1.5 days

  • 1 day

  • 5 days

  • 4 days

Explicação

Questão 123 de 128

1

The radioactive isotope Cobalt-60 decays into Nickel-60 by beta emission, with a half life of 5.3 years. If we start with 100 gram of Co-60, after how many years will we have only 390 milligrams of it left?

Selecione uma das seguintes:

  • 20

  • 42

  • 89

  • 6

Explicação

Questão 124 de 128

1

The activity of Carbon-14 in the living organism today is 15.3 disintegrations per minute, per gram. Half-life of Carbon-14 is 5730 years. If the activity of an archaeological sample, due to the carbon-14 is 3.825 disintegrations per min, per gram, how old is the sample?

Selecione uma das seguintes:

  • 2865

  • 5730

  • 11460

  • 22920

Explicação

Questão 125 de 128

1

The binding energy of a Helium nucleus is 4.5 x 10^-12 Joules (28.4 MeV). What is the total binding energy of 4-grams (one mol.) of Helium that has avogadro's number NA= 6.02 x 10^23 of nuclei, when this mass is converted into radiant energy in the interior of the Sun?

Selecione uma das seguintes:

  • 1.7 x 10^11 J

  • 2.7 x 10^12 J

  • 1.2 x 10^10 J

  • 3.4 x 10^13 J

Explicação

Questão 126 de 128

1

The pair production and annihilation refer to the simultaneous production of a particle and its anti-particle by two energetic gamma-ray photons, near a nucleus, and the destruction of a particle and an anti-particle, as a result of collision between them, these particles and anti-particles can be _____

Selecione uma das seguintes:

  • electron and positron

  • proton and electron

  • proton and neutron

  • two neutrons

Explicação

Questão 127 de 128

1

In the following fission reaction, the atomic number Z and mass number of nucleus A of the unknown element Y are:
(0/1)n + (92/235)U --> (53/135)I + (Z/A)Y + (0/2)n

Selecione uma das seguintes:

  • 38, 102

  • 39, 99

  • 39, 100

  • 37, 100

Explicação

Questão 128 de 128

1

If a light-weight stable nucleus has 12 neutrons, the atomic mass is expected to be _____. (1 atomic mass unit = 1.66 x 10^-27 kg).

Selecione uma das seguintes:

  • 18 amu

  • 24 amu

  • 36 amu

  • 6 amu

Explicação