# MCQ | Current Electricity

QUIZ TEST – I

Question:1. By increasing the temperature the resistance of a conductor

(A) increases.

(B) decreases.

(C) remains constant.

(D) initially increases then decreases.

Ans: (A)

Question:2. A battery of emf V volts, resistance R1 & R2, a condenser C and switches S1 and S2 are connected in a circuit as shown in figure. The capacitor C gets fully charged to V volts when (A) S1 & S2 are both closed

(B) S1 & S2 are both open

(C) S1 closed and S2 open

(D) S2 closed & S1 open.

Ans: (C)

Question:3. The equivalent resistance of a circuit between A and B is (A) 3 Ω

(B) zero.

(C) 6 Ω

(D) 3/2 Ω

Ans: (D)

Question:4. In the circuit shown in figure, the voltmeter reading would be (A) 0 volt.

(B) 0.5 volt.

(C) 1 volt.

(D) 2 volt.

Ans: (A)

Question:5. The V-I graph for a conductor at temperatures T1 and T2 are as shown in the figure, (T2 – T1) is proportional to (A) cos 2θ

(B) sin 2θ

(C) cot2θ

(D) tan 2θ

Ans: (C)

Question:6. If a copper wire is stretched to make it 0.1 % longer. The percentage change in its resistance is

(A) 0.2 % increase

(B) 0.2% decrease

(C) 0.1 % increase

(D) 0.1 % decrease

Ans: (A)

Question:7. In the circuit shown in figure E1 = 7V, E2 = 7V R1 = R2 = 1 Ω and R3 = 3 Ω respectively. The current through the resistance R3 is (A) 2A

(B) 3.5A

(C) 1.75A

(D) none of these

Ans: (A)

Question:8. The figure shows in apart of an electric circuit, then the current I is (A) 1 A

(B) 3A

(C) 2 A

(D) 4 A

Ans: (B)

Question:9. A cell of e.m.f E and internal resistance r is connected across a resistance r. The potential difference between the terminals of the cell must be

(A) E

(B) E/2

(C) E/4

(D) 3E/2

Ans: (B)

Question:10. A conductor carries a current of 50 mA if the area of cross-section of the conductor is 50 mm2 then value of the current density in Am-2 is

(A) 0.5

(B) 1

(C) 10-1

(D) 3/10

Ans: (B)

Question:11. In the adjoining circuit, the battery E1 has an E.M.F. of 12 volts and zero internal resistance. While the battery E2 has an E.M.F. of 2 volts if the galvanometer G reads zero than the value of the resistance X in ohms is (A) 10

(B) 100

(C) 14

(D) 200

Ans: (B)

Question:12. Nine similar resistors of resistance R are connected as shown in the figure. Equivalent resistance between points A and B is (A) 3R/5

(B) 4R/3

(C) 9R/5

(D) R

Ans: (A)

Question:13. Referring to the adjoining circuit which of the following is/are true (A) R = 80 ohms

(B) R = 6 ohms

(C) R = 10 ohms

(D) Potential difference between points A & E is 2V

Ans: (B)

Question:14. In a gas discharge tube if 3 × 1018 electrons are flowing per sec from left to right and 2 × 1018protons are flowing per second from right to left a given cross section the magnitude and direction of current through the cross section

(A) 0.48 A, left to right

(B) 0.48 A, right

(C) 0.80 A, left to right

(D) 0.80 A, right to left

Ans: (D)

Question:15. In a portion of some large electrical network, current in certain branches are known. The values of (VA – VB) and (VC – VD) are X and Y respectively. Where x and y are (A) X = 29 V, Y = 26 V

(B) X = 58 V, Y = – 52 V

(C) X = -58 V, Y = -52 V

(D) X = -29 V, Y = -26 V

Ans: (C)

Question:16. A 50 V battery is connected across a 10 Ω resistor and a current of 4 .76 A flows. The internal resistance of the battery is

(A) 0.5 Ω

(B) 0.1 Ω

(C) 0.2 Ω

(D) 0.3 Ω

Ans: (A)

Question:17. For the circuit shown which of the following statements is true ? (A) with S1 closed, V1 = 1 5 V, V2 = 20 V

(B) with S3 closed V1 = V2 = 25 V

(C) with S1 & S2 closed, V1 = V2 = 0

(D) with S1 and S3 closed, V1 = 30 V, V2 = 20 V

Ans: (D)

Question:18. In the given circuit ammeter and voltmeter are ideal and battery of 6V has internal resistance 1 Ω . The reading of voltmeter and ammeter is (A) zero, 4/3 Ω

(B) 4/3 V, zero

(C) 6 A, 0.1 A

(D) 3.6 V, 0.6 A

Ans: (D)

Question:19. The maximum power dissipated by external resistance R by a cell of an external emf E and internal resistance r is E2/4R which is obtained for

(A) R < r

(B) R > r

(C) R = r

(D) any value of R.

Ans: (C)

Question:20. An electric current of 16 A exists in a metal wire of cross section 10-6 m2 and length 1 m . Assuming one free electrons per atom. The drift speed of the free electrons in the wire will be
(Density of metal = 5 × 103 kg/m3, atomic weight = 60)

(A) 5 × 10-3 m/s

(B) 2 × 10-3 m/s

(C) 4 × 10-3 m/s

(D) 7.5 × 10-3 m/s