Current Electricity Mock Test – Class 12 Physics

1. The graph described below gives voltage and current data for a device.

At this operating point, the resistance and power are

2. Current electricity mainly studies what kind of electrical situation?

3. Study the table for a potentiometer experiment.

The row with the unsuitable validity marking is

4. A Wheatstone bridge has , , and . For balance, the resistance should be

5. Using and , the mobility of a charge carrier is

6. A voltmeter is connected in parallel with a resistor because it measures

7. The derivation from microscopic Ohm's law to for a uniform wire uses which pair of relations most directly?

8. Consider the following statements about current in a circuit.
I. Electric current is a scalar quantity in ordinary circuit analysis.
II. A direction is still associated with current flow in a wire.
III. Conventional current in a metal is always along electron drift.

9. A conductor gives these readings at constant temperature:

The best interpretation of the data is that the conductor is approximately ohmic with resistance close to

10. When a steady electric field is applied inside a metallic conductor, collisions of electrons with lattice ions mainly

11. In an ohmic conductor, Ohm's law states that the potential difference across the conductor is proportional to current provided

12. A cell is balanced at on a potentiometer wire. The balance length for a cell on the same wire is

13. A lamp is used for . The electrical energy consumed is

14. Two identical cells are first connected in series aiding and then in parallel with the same polarity. The external resistance is very small compared with the internal resistance of each cell. The parallel connection can give a larger current mainly because

15. Two lamps are connected so that each lamp is joined directly across the same two terminals of a cell. The arrangement is parallel because

16. A resistor has across it and through it under constant physical conditions. Its resistance is

17. In deriving the Wheatstone bridge balance condition, the key reason the galvanometer branch can be ignored at balance is that

18. A potentiometer wire has a potential difference of across it

19. A metal resistor has and . The temperature rise needed to increase its resistance by is

20. Study the table for a parallel circuit.

The unsuitable row is

21. Two resistors and are connected in parallel. Their equivalent resistance is

22. A metal wire is connected to a cell so that electrons drift from right to left through the wire. The conventional current in the same wire is directed

23. During a potentiometer comparison, for two cells on the same wire. If the second cell has emf , the emf of the first cell is

24. A cell with internal resistance supplies a current of . Its terminal potential difference is

25. Match the circuit part with its usual role in a simple closed circuit.

26. The expression is needed instead of simply when

27. In a two-loop circuit, the junction rule gives . The left loop equation is , and the right loop equation is . The current is

28. The same resistor is represented on two different graphs. One graph plots against , and the other plots against . If the resistor has resistance , the slopes of the two graphs respectively are

29. A device has when , but when . What conclusion follows from these two readings?

30. In finding internal resistance by a potentiometer, the open-circuit balance length is larger than the loaded balance length because

31. A student writes the junction equation . This equation means

32. Electric current through a wire is defined as the

33. When the series resistance in the primary circuit is increased, the potentiometer wire has a smaller potential gradient. For the same test cell, the new balance length becomes

34. A resistor and a resistor are connected in series in one branch. This branch is connected in parallel with a resistor. The equivalent resistance of the whole network is

35. A copper wire of length , area , and resistivity is connected across a source. If the electron number density is and , the drift speed of electrons is

36. A resistor is connected in parallel with a series combination of and . The whole network is connected across . The current through the branch is

37. A balanced Wheatstone bridge has , , , and . If the galvanometer branch is removed after balance is achieved, the equivalent resistance between the battery terminals is

38. Three identical cells, each of emf and internal resistance , are connected in series aiding to a resistor of . The current is

39. A cell of internal resistance is connected to a parallel combination of and . The power dissipated in the branch is

40. A series combination contains resistors , , and . Its equivalent resistance is larger than each individual resistance because

41. A conductor has conductivity and an electric field inside it. The current density is

42. Use the circuit description below.

If , the current through the branch is

43. Use the arrangement described below.

The current through the branch is

44. Consider the following statements about limitations of Ohm's law.
I. Ohm's law applies only under constant physical conditions.
II. A diode is an example of a device with non-linear - behavior.
III. Any curved - graph through the origin still represents constant resistance.

45. Use the loop equation below for a single closed circuit:

The physical circuit represented by this equation is most directly

46. For an ohmic material, the slope of an -versus- graph is . The conductivity of the material is

47. If the potential gradient in a potentiometer becomes too large, For a small change in the emf being measured, the corresponding change in balance length becomes

48. A thermistor made from a semiconductor is used in a temperature-sensing circuit. Its resistance falls when temperature rises. This behavior is best described as

49. Use the loop described below.

The loop current is

50. During charging of a cell, current is forced into the positive terminal of the cell. In that case, the terminal potential difference is generally