Monday, May 2, 2011

Electricity - Multiple Choice Questions Test

Question 1
Question: Which of the following statements does not represent ohm's law?

1. current / potential difference = constant
2. potential difference / current = constant
3. potential difference = current x resistance
4. current = resistance x potential difference
Answer: 4

Question 2
Question: The unit of current is _____________.

1. ampere
2. watt
3. volt
4. coulomb
Answer: 1

Question 3
Question: The potential difference required to pass a current 0.2 A in a wire of resistance 20W is ____.

1. 100 V
2. 4 V
3. .01 V
4. 40 V
Answer: 2

Question 4
Question: The resistance of an electric bulb drawing 1.2 A current at 6.0 V is ___________.

1. 0 .5 W
2. 5 W
3. 0.2 W
4. 2 W


Answer: 2

Question 5
Question: The unit of resistivity is ____________.

1. ohm
2. ohm / m
3. ohm-m
4. mho
Answer: 3

Question 6
Question: Two resistances of 100 W and zero ohm are connected in parallel. The overall resistance will be

1. 100 W
2. 50 W
3. 25 W
4. zero ohm
Answer: 1

Question 7
Question: Three resistors 2 W , 3 W and 4 W are connected so that the equivalent resistance is 9 W . The resistors are connected _________.

1. all in series
2. all in parallel
3. 2 W and 3 W in parallel and the combination in series with 4 W
4. 2 W and 3 W in series and the combination in parallel to 4 W


Answer: 1

Question 8Back to Top
Question: In the figure,


1. 6 W , 3 W and 9 W are in series
2. 9 W and 6 W are in parallel and the combination is in series with 3 W
3. 3 W , 6 W and W are in parallel
4. 3 W , 6 W are in parallel and 9 W is in series

Answer: 4

Question 9
Question: The resistance across AB is


1. 4
2. 1
3. 2
4. 0 .5

Answer: 2

Question 10
Question: When a current 'I' flows through a resistance 'R' for time 't' the electrical energy spent is given by ___________.

1. I R t
2. I2 R t
3. I R2 t
4. I 2 R / t

Answer: 2

Question 11
Question: Kilowatt - hour is the unit of ______________.

1. potential difference
2. electric power
3. electrical energy
4. charge
Answer: 3

Question 12
Question: When a fuse is rated 8 A, it means _____________.

1. it will not work if current is less than 8 A
2. it has a resistance of 8 W
3. it will work only if current is 8 A
4. it will melt if current exceeds 8 A

Answer: 4

Question 13
Question: The device used for measuring potential difference is known as _____________.

1. potentiometer
2. ammeter
3. galvanometer
4. voltmeter
Answer: 4

Question 14
Question: The work done in moving a unit positive charge across two points in an electric circuit is a measure of ___________.

1. current
2. potential difference
3. resistance
4. power
Answer: 2

Question 15
Question: The potential at a point is 20 V. The work done to bring a charge of 0.5 C from infinity to this point will be ________.

1. 20 J
2. 10 J
3. 5 J
4. 40 J
Answer: 2

Question 16
Question: Joule / Coulomb is same as ______________.

1. watt
2. volt
3. ampere
4. ohm
Answer: 2

Question 17
Question: The free electrons of a metal _____________.

1. do not collide with each other
2. are free to escape through the surface
3. are free to fall into the nuclei
4. are free to move anywhere in the metal
Answer: 4

Question 18
Question: The path of a free electron in a metal is ___________.

1. parabolic
2. circular
3. a straight line
4. zig zag
Answer: 4

Question 19
Question: Heat produced in a current carrying wire in 5s is 60 J. The same current is passed through another wire of half the resistance. The heat produced in 5 s will be _____________.

1. 60 J
2. 30 J
3. 15 J
4. 120 J
Answer: 2

Question 20
Question: The current in a wire ______________.

1. depends only on the potential difference applied
2. depends only on the resistance of the wire
3. depends on both resistance and potential difference
4. does not depend on resistance and potential difference
Answer: 3

Question 21
Question: When there is an electric current passing through a wire, the particles moving are _____________.

1. electrons
2. protons
3. atoms
4. ions
Answer: 1

Question 22
Question: A positive charge released from rest __________.

1. moves towards the regions of lower potential
2. moves towards the regions of higher potential
3. moves towards the regions of equal potential
4. does not move
Answer: 1

Question 23
Question: Three equal resistances when combined in series are equivalent to 90 W . Their equivalent resistance when combined in parallel will be __________.

1. 270 W
2. 30 W
3. 810 W
4. 10 W


Answer: 4

Question 24
Question: An battery is used to ________________.

1. maintain a potential difference
2. measure electric current
3. measure electric potential
4. safeguard against short - circuit
Answer: 1

Question 25
Question: Ohm's law relates potential difference with ___________.

1. power
2. energy
3. current
4. time
Answer: 3

Question 26
Question: Which of the following is an ohmic resistor?

1. Diode
2. Germanium
3. Nichrome
4. Diamond
Answer: 3

Question 27
Question: The resistivity of a wire depends on ____.

1. length
2. material
3. area of cross- section
4. length, material and area of cross- section
Answer: 4

Question 28
Question: For which of the following substances, resistance decreases with temperature?

1. Copper
2. Platinum
3. Mercury
4. Carbon
Answer: 4

Question 29
Question: Four cells each of e.m.f 'E' are joined in parallel to form a battery. The equivalent e.m.f of the battery will be _______.

1. 4 E
2. E
3. E / 4
4. E = 0
Answer: 2

Question 30
Question: Two electric bulbs have resistances in the ratio 1:2. If they are joined in series, the energy consumed in them are in the ratio _________.

1. 1:2
2. 2:1
3. 4:1
4. 1:1
Answer: 2

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