# Physics Class-12 Chapter-3 Current Electricity VVI Objective Questions

Q.1. kilowatt hour is the unit of

(A) energy

(B) power

(C) torque

(D) force

Ans:- (A)

Q.2 Electron volt is a measure of

(A) charge

(B) potential difference

(C) current

(D) energy

Ans:- (D)

Q.3. To increase sensitivity of a potentiometer its

(A) area should be increased

(B) current should be increased

(C) current should be decreased

(D) length should be increased

Ans:-(D)

Q.4. The SI unit of electrical resistance is

(A) ohm

(C) coulomb

(D) siemen

Ans:- (A)

Q.5. The SI unit of electrical conductance is

(A) ohm

(B) siemen (S)

(C) ampere

(D) volt

Ans:- (B)

Q.6. 1 Faraday is equal to

(A) 1 ampere

(B) 96,500 coulomb

(C) 1.6 × 10¹⁹ Coulomb

(D) None of these

Ans:- (B)

Q.7. The S.I. unit of electrical conductivity  (

σ) is

(A) siemen

(B) siemen/meter

(C) ohm

(D) ohm / meter

Ans:- (B)

Q.8. Electric current is

(A) a vector quantity

(B) a scalar quantity

(C) vector and scalar both

(D) none of these

Ans:- (B)

Q.9. Which of the following is not a unit of electric current

(A) ampere-second

(B) coulomb/second

(C) ampere

(D) none of these

Ans:- (A)

Q.10. When a body is charged its mass

(A) increases

(B) decreases

(C) remains same

(D) may increase or decrease

Ans:- (D)

Q.11. When electric current passes through a conductor is resistance

(A) decreases

(B) increases

(C) remains the same

(D) none of these

Ans:- (B)

Q.12. If that if the temperature is increased the resistivity of a metal

(A) increases

(B) decreases

(C) remains same

(D) none of these

Ans:- (A)

Q.13. Which of the following has highest electrical conductivity ?

(A) copper

(B) aluminium

(C) silver

(D) gold

Ans:- (C)

Q.15. Which of the following has highest resistivity ?

(A) Mercury

(B) copper

(C) nichrome

(D)none of these

Ans:- (C)

Q.16. Tungsten is used for lamp filaments because of its

(A) high resistivity

(B) low resistivity

(C) high melting point

(D) low melting point

Ans:- (C)

Q.17. The SI unit of electrical power is

(A) volt

(B) watt

(C) ampere

(D) Ohm

Ans:- (B)

Q.18. The wheatstone bridge is not suitable to measure

(A) very high resistance

(B) very low resistance

(C) both very high and very low resistances

(D) none of these

Ans:- (C)

Q.19. Wheatstone bridge is suitable for measuring resistances of

(A) very low value

(B) moderate value

(C) high value

(D) none of these

Ans:- (B)

Q.20. A wire is resistance R is pulled to double its length, its new resistances is

(A) 4R

(B) R

(C) 2R

(D) none of these

Ans:- (A)

Q.21. Kirchhoff’s first law (or current law, point rule) obeys the law of conservation of

(A) charge

(B) momentum

(C) energy

(D) mass

Ans:- (A)

Q.22. Kirchhoff’s second law (or loop law, mesh law) obeys the law of conservation of

(A) charge

(B) momentum

(C) energy

(D) mass

Ans:- (C)

Q.23. Ohm’s law does not obey for

(A) insulator

(B) semiconductor

(C) diode

(D) all of the above

Ans:- (D)

Q.24. A wire is stretched 40%. the percentage change in its resistance is

(A) 80%

(B) 96%

(C) 40%

(D) None

Ans:- (B)

Q.25. Dimensional formula of electric field(E) is

(A) [MLT⁻³A⁻¹]

(B) [MLA]

(C) [MLT²A⁻¹]

(D) None of these

Ans:- (A)

Q.26. 1 ampere is equivalent to

(A) 1C

(B) 1 coulomb-second

(C) coulomb/second

(D) none of these

Ans:- (C)

Q.27. Metals are good conductors of electricity because they have

(A) a small number of free electrons

(B) no free electron

(C) large number of free electrons

(D) none of these

Ans:- (C)

Q.28. If the temperature of an electrolyte is increased, its conductivity will

(A) decrease

(B) remains the same

(C) increases

(D) none of these

Ans:- (C)

Q.29. A wire of resistivity ρ is stretched of three times its length. what will be its new resistivity ?

(A) 3ρ

(B) 4ρ

(C) ρ (no change in resistivity)

(D) none of these

Ans:- (C)

Q.30. A current flows in a wire of resistance 5Ω having potential difference 7 volt for 20 minutes. the heat produced is

(A) 140 cal

(B) 280 cal

(C) 700 cal

(D) 2800 cal

Ans:- (D)

Q.31. When the temperature of the conductor decreases then the mobility of electron will be

(A) increase

(B) decrease

(C) remains same

(D) none of these

Ans:- (B)

Q.32. Power of electric circuit is

(A) VR

(B) V²R

(C) V²/R

(D) none of these

Ans:- (C)

Q.33. Three resistors of resistance 1 Ω each are connected to from a triangle. The resistance between any two terminals is

(A) 30 Ω

(B) 1/3 Ω

(C) 2/3 Ω

(D) 3/2 Ω

Ans:- 2/3 Ω

Q.34. Two resistors of resistances 12Ω  and 6Ω  are connected in parallel. the equivalent resistance is

(A) 24 Ω

(B) 12 Ω

(C) 6 Ω

(D) 4 Ω

Ans:- (D)

Q.35. These are three resistors of the same resistance. The ratio of their equivalent series resistance to their equivalent parallel resistance is

(A) 1:3

(B) 3:1

(C) 1:9

(D) 9:1

Ans:- (D)

Q.36. A copper wire of diameter 1 mm carries a current 6.28 A.  the current density in the wire in A/m² is

(A) 6.28×10⁶

(B) 8×10⁶

(C) 6.28×10⁻⁶

(D) 8×10⁻⁶

Ans:- (B)

Q.37. A current flows in a wire of resistance 5Ω  having potential difference 7 volt for 20 minutes. the heat produced is

(A) 140 cal

(B) 280 cal

(C) 700 cal

(D) 2800 cal

Ans:- (D)

Q.38. A cell of e.m.f. 1.5 V is connected with an ammeter of resistance 0.05 Ω. If the current in the circuit is 2.0 A, the internal resistance of the cell is

(A) 1Ω

(B) 0.9 Ω

(C) 0.8 Ω

(D) 0.7 Ω

Ans:- (D)

Q.39. The number of different combinations made out of three equal resistors taken together is

(A) two

(B) three

(C) four

(D) six

Ans:- (C)

Q.40. When the temperature of a metallic wire is increased then the product of conductivity and resistivity of that wire is

(A) increased

(B) decreased

(C) remains unchanged

(D) none of these

Ans:- (C)

Q.41. The temperature coefficient of resistivity is always negative

(A) for metals

(B) for semiconductor

(C) for insulator

(D) none of these

Ans:- (B)

Q.42. The temperature coefficient of resistivity is always positive

(A) for metals

(B) for semiconductor

(C) both A and B

(D) none of these

Ans:- (B)