Current Electricity Quiz - ICSE Class 10 Physics

Free practice quiz: Current Electricity (ICSE Class 10 Physics). 50 multiple-choice questions with answers and explanations. Play online, no sign-up needed.

This ICSE Class 10 Physics practice quiz has 50 multiple-choice questions on Current Electricity, and 50 of them come with an explanation. Try the 5 sample questions below (tap an option to check yourself), then play the full quiz online. No sign-up needed.

Sample questions

1. A wire of resistance R is stretched to thrice its original length. What will be its new resistance?

   1. R/3
   2. 3R
   3. 9R
   4. R/9
   Show answer

   Answer: C. 9R

   When a wire is stretched, its volume remains constant. Let the original length be L and the original cross-sectional area be A. The resistance R = ρ(L/A). When stretched to thrice its original length, the new length L' = 3L. Let the new cross-sectional area be A'. Since volume is constant, AL = A'L'. So, A' = AL/L' = AL/(3L) = A/3. The new resistance R' = ρ(L'/A') = ρ((3L)/(A/3)) = ρ(9L/A) = 9 * ρ(L/A) = 9R.

2. Which instrument is used to measure electric current?

   1. Voltmeter
   2. Ammeter
   3. Ohmmeter
   4. Galvanometer
   Show answer

   Answer: B. Ammeter

   An ammeter is an instrument used to measure electric current in a circuit. It is always connected in series with the component through which the current is to be measured.

3. If the length of a conductor is doubled and its area of cross-section is also doubled, its resistance will:

   1. Remain unchanged
   2. Be doubled
   3. Be halved
   4. Be quadrupled
   Show answer

   Answer: A. Remain unchanged

   The resistance of a conductor is given by R = ρ(L/A). If the length L is doubled (L' = 2L) and the cross-sectional area A is also doubled (A' = 2A), then the new resistance R' = ρ(L'/A') = ρ((2L)/(2A)) = ρ(L/A) = R. Thus, the resistance remains unchanged.

4. Which of the following is the correct combination for a voltmeter?

   1. High resistance, connected in series
   2. Low resistance, connected in series
   3. High resistance, connected in parallel
   4. Low resistance, connected in parallel
   Show answer

   Answer: C. High resistance, connected in parallel

   A voltmeter is used to measure the potential difference across a component. To ensure that it draws negligible current from the circuit and does not significantly alter the voltage it is measuring, it must have a very high resistance. It is connected in parallel with the component across which the voltage is to be measured.

5. If a conductor carries a current of 1 Ampere and has a potential difference of 1 Volt across it, then its resistance is:

   1. 1 Ohm
   2. 1 Volt
   3. 1 Ampere
   4. 1 Watt
   Show answer

   Answer: A. 1 Ohm

   According to Ohm's Law, R = V/I. If V = 1 Volt and I = 1 Ampere, then R = 1 V / 1 A = 1 Ohm (Ω).

More questions in this quiz

Answers and explanations are in the full quiz.

1. Two resistors of resistances R1 and R2 are connected in series. If R1 = 10 Ω and R2 = 20 Ω, what is the equivalent resistance?
2. If a current of 2 A flows through a resistor of 5 Ω, what is the potential difference across the resistor?
3. Which of the following statements about electric power is incorrect?
4. A bulb is rated 100 W, 220 V. What is the resistance of its filament?
5. What is the unit of electric current?
6. A circuit has a resistance of 10 Ω and a voltage of 5 V. What is the current flowing through the circuit?
7. Which quantity is represented by the symbol 'ρ' in the context of resistance?
8. If a wire of resistance R is doubled in length and its cross-sectional area is halved, what will be its new resistance?
9. In a series circuit, if one component fails, what happens to the rest of the circuit?
10. If the voltage across a circuit is kept constant and the resistance is doubled, what happens to the current?
11. When resistors are connected in parallel, which of the following is true?
12. A 60 W bulb and a 100 W bulb are connected in series across a 220 V supply. Which bulb will glow brighter?
13. The drift velocity of electrons in a conductor is proportional to:
14. A kilowatt-hour (kWh) is a unit of:
15. If the number of electrons flowing through a conductor in 1 second is 'n', and the charge of one electron is 'e', then the current (I) is:
16. A heater element is made of a material which has:
17. Two identical resistors are connected first in series and then in parallel. The ratio of the equivalent resistance in series to the equivalent resistance in parallel is:
18. Which of the following statements is INCORRECT regarding electric cells?
19. A fuse wire is used in domestic circuits to:
20. The resistance of a wire is proportional to its:
21. If a wire of resistance R is melted and recast so that its volume remains the same but its length is halved, what will be its new resistance?
22. What is the unit of electric potential difference?
23. When a number of resistors are connected in parallel, the effective resistance is:
24. Which of the following materials has the highest resistivity at room temperature?
25. A battery of 12 V is connected to a resistor of 6 Ω. The current flowing through the resistor is:
26. The heating effect of electric current is utilized in:
27. If the voltage across a conductor is doubled, and its resistance is also doubled, what happens to the current?
28. If the current in a circuit is 5 A and the power dissipated is 100 W, what is the potential difference across the circuit?
29. In a parallel circuit with three resistors R1, R2, and R3, if R1 is increased, the total current from the source will:
30. The resistivity of a conductor depends on:
31. When a wire of uniform cross-sectional area is stretched, its resistance:
32. Which of the following statements about electric charge is correct?
33. A device that converts electrical energy into mechanical energy is called a:
34. If four identical resistors are connected in series, and the equivalent resistance is 40 Ω, what is the resistance of each resistor?
35. The resistance of a conductor is inversely proportional to its:
36. Which of the following statements about a parallel combination of resistors is always true?
37. A resistor of 10 Ω is connected in series with a resistor of 20 Ω and then this combination is connected in parallel with a resistor of 15 Ω. What is the total equivalent resistance?
38. The drift velocity of electrons in a conductor is independent of:
39. If 5 A of current flows through a wire for 10 seconds, the total charge that has passed through the wire is:
40. Which of the following is the correct relation for power dissipation in a resistor?
41. A wire of resistance 20 Ω is stretched so that its length is doubled. What will be the new resistance?
42. In a parallel circuit, if one resistor is removed, the total current from the source will:
43. A circuit contains a battery, a switch, and a bulb. If the switch is closed, the bulb lights up. This demonstrates:
44. The SI unit of electric charge is the:
45. If a 2 Ω resistor and a 4 Ω resistor are connected in parallel, what is the equivalent resistance?

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