Current Electricity Multiple Choices Questions And Answer In English -01

1. The resistance of a conductor varies inversely as

(a) length

(b) area of cross-section

(c) temperature

(d) resistivity

Ans: b

2. With rise in temperature the resistance of pure metals

(a) increases

(b) decreases

(c) first increases and then decreases

(d) remains constant

Ans: a

3. With rise in temperature the resistance of semi-conductors

(a) decreases

(b) increases

(c) first increases and then decreases

(d) remains constant

Ans: a

4. Two resistors are said to be connected in series when

(a) same current passes in turn through both

(b) both carry the same value of current

(c) total current equals the sum of branch currents

(d) sum of IR drops equals the applied e.m.f.

Ans: a

5. Which of the following statement is true both for a series and a parallel D.C. circuit?

(a) Elements have individual currents

(b) Currents are additive

(c) Voltages are additive

(d) Power are additive

Ans: d

6. Which of the following materials has a negative temperature co-efficient of resistance?

(a) Copper

(b) Aluminum

(c) Carbon

(d) Brass

Ans: c

7. Ohm’s law is not applicable to

(a) vacuum tubes

(b) carbon resistors

(c) high voltage circuits

(d) circuits with low current densities

Ans: a

8. Which is the best conductor of electricity ?

(a) Iron

(b) Silver

(c) Copper

(d) Carbon

Ans: b

9. For which of the following ‘ampere second’ could be the unit ?

(a) Reluctance

(b) Charge

(c) Power

(d) Energy

Ans: b

10. All of the following are equivalent to watt except

(a) (amperes) ohm

(b) joules/sec.

(c) amperes x volts

(d) amperes/volt

Ans: d

11. A resistance having rating 10 ohms, 10 W is likely to be a

(a) metallic resistor

(b) carbon resistor

(c) wire wound resistor

(d) variable resistor

Ans: c

12. Which one of the following does not have negative temperature co-efficient ?

(a) Aluminium

(b) Paper

(c) Rubber

(d) Mica

Ans: a

13. Varistors are

(a) insulators

(6) non-linear resistors

(c) carbon resistors

(d) resistors with zero temperature coefficient

Ans: b

14. Insulating materials have the function of

(a) preventing a short circuit between conducting wires

(b) preventing an open circuit between the voltage source and the load

(c) conducting very large currents

(d) storing very high currents

Ans: b

15. Which of the following quantities remain the same in all parts of a series circuit ?
(a) Voltage
(b) Current
(c) Power
(d) Resistance
Ans: b

16. A 40 W bulb is connected in series with a room heater. If now 40 W bulb is replaced by 100 W bulb, the heater output will
(a) decrease
(b) increase
(c) remain same
(d) heater will burn out
Ans: b

17. In an electric kettle water boils in 10 m minutes. It is required to boil the boiler in 15 minutes, using same supply mains
(a) length of heating element should be decreased
(b) length of heating element should be increased
(c) length of heating element has no effect on heating if water
(d) none of the above
Ans: a

18. An electric filament bulb can be worked from
(a) D.C. supply only
(b) A.C. supply only
(c) Battery supply only
(d) All above
Ans: d

19. Resistance of a tungsten lamp as applied voltage increases
(a) decreases
(b) increases
(c) remains same
(d) none of the above
Ans: b

20. Whether circuit may be AC. or D.C. one, following is most effective in reducing the magnitude of the current.
(a) Reactor
(b) Capacitor
(c) Inductor
(d) Resistor
Ans: d