20625155
Descrição
Quiz por Owen Ryan Ang, atualizado more than 1 year ago
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Criado por Owen Ryan Ang
quase 5 anos atrás
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Questão 1
Questão
What are the minimum requirements to cause the flow of current?
Responda
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A voltage source, an ammeter, a conductor and an insulator
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A voltage source, a switch and a resistor
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A voltage source and a conductor
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A voltage source, a conductor and an insulator
Questão 2
Questão
Out of the following, select the best conductor of electricity.
Responda
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Graphite
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China Clay
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Porcelain
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None of these
Questão 3
Questão
Which of the following statements is correct?
Responda
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The resistance does not play an important role in electrical engineering.
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The resistance of a wire does not depend upon its material.
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The resistance of most of the materials is independent of the temperature.
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The resistance of conductor is the hindrance by which the conductor opposes the flow of the current.
Questão 4
Questão
Resistance of a conductor increases when
Responda
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its length increases
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its area increases
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both length and area increases
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specific resistance is kept constant
Questão 5
Questão
The specific resistance ρ depends upon
Responda
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The area of cross-section and the length of the conductor
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The material of the conductor, its area of cress-section and length
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The nature of the material of the conductor only
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The area of cross-section of the conductor
Questão 6
Questão
The specific resistance ρ is defined as
Responda
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resistance of a conductor which has a length of 1 m and cross-section of 1 m2 at 20C
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resistance of any conductor at 25C
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resistance of any conductor at 20C
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resistance of a conductor which has a length of 1 m and cross-section of 1 cm2 at 20C
Questão 7
Questão
The resistance of a conductor, when its temperature is increased
Responda
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remains constant
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increases
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varies
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decreases
Questão 8
Questão
It was experimentally found by James Prescott Joule that the heat produced in a current carrying conductor is proportional to
Responda
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the square of the current
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square of resistance
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the current
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inversely proportional to time
Questão 9
Questão
The value of Joule's mechanical equivalent of heat, J, is equal to
Responda
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4.2 calories per Joule
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2.4 Joules per calorie
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4.2 Joules per calorie
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4.2 Joules
Questão 10
Questão
Temperature coefficient of a conductor is defined as the
Responda
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increase in resistance per ohm per degree centigrade
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increase in resistance per degree centigrade
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increase in resistance per degree absolute
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decrease in resistance per ohm per degree centigrade
Questão 11
Questão
When current flows in a conductor, heat is produced because
Responda
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heat α I²
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of electronic collision
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of interatomic collision
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of Joule's law
Questão 12
Questão
Heating effect of current has undesirable side effect in
Responda
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electric oven
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electric iron
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immersion heater
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vacuum cleaner
Questão 13
Questão
The resistance of carbon (filament in carbon-filament lamps) when its temperature is decreased
Responda
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increases
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decreases
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remains the same
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increases enormously
Questão 14
Questão
The curve representing Ohm's law is
Responda
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a parabola
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linear
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sine function
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a hyperbola
Questão 15
Questão
The condition in Ohm's law is that
Responda
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ratio V/I should be constant
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current should be proportional to voltage
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the temperature should remain constant
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the temperature should vary
Questão 16
Questão
Ohm's law does not apply to
Responda
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conductors
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conductors when there is change in temperature
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semiconductor
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a.c. circuit
Questão 17
Questão
Ohm's law is applicable to
Responda
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electric arc
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rectifying devices
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gas discharge lamps
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none of these
Questão 18
Questão
Ohm's law can be applied with certain reservations to
Responda
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rectifying devices
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semiconductors
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electrolytes
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thermionic valves
Questão 19
Questão
The presence of an electric current is made known by
Responda
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flashing
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effects produced
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cracking
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electric shock
Questão 20
Questão
An electric current can neither be ____ nor ____.
Responda
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felt, seen
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seen, touched
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seen, produced by any effect
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produced, felt
Questão 21
Questão
The presence of the current is only made known by the effect it produces. Three important effects are
Responda
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heating, electric shock and generation
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generation, chemical and electric shock
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heating, magnetic and electric shock
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heating, magnetic and chemical
Questão 22
Questão
Voltage applied across a circuit, acts as
Responda
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mass of electrons
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negative ions
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a component of current
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a force
Questão 23
Questão
In a series circuit the current is
Responda
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constant
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always zero
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proportional to the resistance
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different from resistors
Questão 24
Questão
In a parallel circuit the potential difference across the resistance
Responda
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varies
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is different from the applied voltage
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is sometimes constant
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is always constant
Questão 25
Questão
The resistance R1 and R2 are connected in parallel. The ratio of values of resistance R1 : R2 is 4 : 1. The currents in R1 : R2 will be equal to
Responda
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1 : 4
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1 : 1
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4 : 1
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4 : 4
Questão 26
Questão
A resistance of 4 ohms is connected across 100 V supply. When another resistor 'R' ohms is connected in parallel with 4 ohms, the total current taken from supply was found to be 50 A. The value of resistance 'R' is
Responda
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2 ohms
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3 ohms
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5 ohms
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4 ohms
Questão 27
Questão
The voltage applied across an electric press was reduced by 50%. The power consumed by the press will be reduced by
Responda
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25%
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75%
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60%
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50%
Questão 28
Questão
Two electric presses are connected in parallel. The resistance of the first press is 100 ohms and that of the second is 300 ohms. The total current taken by both the presses is 4 A. The ratio of current taken by first : second will be equal to
Responda
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2 : 3
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1 : 3
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3 : 1
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1.2 : 3
Questão 29
Questão
Three elements having conductance G1. G2 and G3 are connected in parallel. Their combined conductance will be
Responda
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G1 + G2 + G3
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1/(G1 + G2 + G3)
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(G1G2 + G2G3 + G3G1)/(G1 + G2 + G3)
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1/(1/G1 + 1/G2 + 1/G3)
Questão 30
Questão
Four resistance R1, R2, R3 and R4 are connected in series against 220 V supply. The resistances are such that R1 > R2 > R3 > R4. The least power consumption will be in
Responda
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resistor R1
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resistor R4
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resistor R3
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resistor R2
Questão 31
Questão
When current flows through heater coil it glows but supply wiring does not glow because
Responda
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supply wiring is covered with insulation layer
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current through supply line flows at slower speed
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supply wires are made of superior material
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resistance of heater coil is more than that of supply wires
Questão 32
Questão
Resistors commonly used in power circuits are
Responda
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carbon resistors
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etched circuit resistors
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wire wound resistors
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deposited metal resistors
Questão 33
Questão
International ohm is defined in terms of resistance of
Responda
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a column of mercury
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a cube of carbon
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unit length of metal wire
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a cube of copper
Questão 34
Questão
Which of the following has negative coefficient of resistance?
Responda
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wire wound resistor
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non-metals
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thermistor
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metals
Questão 35
Questão
The current carrying capability of the fuse material depends on
Responda
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length
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material
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cross-sectional area
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all of these
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