Current electricity

11. The resistance of a conductor varies inversely as

Length
Area of cross-section
Temperature
Resistivity

Detailed SolutionThe resistance of a conductor varies inversely as

12. An open resistor, when checked with an ohmmeter reads

Zero
Infinite
High but within tolerance
Low but not zero

Detailed SolutionAn open resistor, when checked with an ohmmeter reads

13. In the case of direct current

Magnitude and direction of current remains constant
Magnitude and direction of current changes with time
Magnitude of current changes with time
Magnitude of current remains constant

Detailed SolutionIn the case of direct current

14. What will be energy used by the battery if the battery has to drive 6.28 x 1018 electrons with potential difference of 20 V across the terminal?

5 joules
10 joules
15 joules
20 joules

Detailed SolutionWhat will be energy used by the battery if the battery has to drive 6.28 x 1018 electrons with potential difference of 20 V across the terminal?

15. When current flows through heater coil it glows but supply wiring does not glow because

Current through supply line flows at slower speed
Supply wiring is covered with insulation layer
Resistance of heater coil is more than the supply wires
Supply wires are made of superior material

Detailed SolutionWhen current flows through heater coil it glows but supply wiring does not glow because

16. One Newton meter is same as

One watt
One joule
Five joules
One joule second

Detailed SolutionOne Newton meter is same as

17. Sparking occurs when a load is switched off because the circuit has high

Resistance
Inductance
Capacitance
Impedance

Detailed SolutionSparking occurs when a load is switched off because the circuit has high

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

Elements have individual currents
Currents are additive
circuit? A. Elements have individual currents B. Currents are additive C. Voltages are additive
Power are additive

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

19. The four bulbs of 40 W each are connected in series swift a battery across them, which of the following statement is true?

The current through each bulb in same
The voltage across each bulb is not same
The power dissipation in each bulb is not same
None of the above

Detailed SolutionThe four bulbs of 40 W each are connected in series swift a battery across them, which of the following statement is true?

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

Same current passes in turn through both
Both carry the same value of current
Total current equals the sum of branch currents
Sum of IR drops equals the applied e.m.f.

Detailed SolutionTwo resistors are said to be connected in series when

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