Question 1. A wire of length /, made of material resistivity ρ is cut into two equal parts. The resistivity of the two parts are equal to,
(a) ρ
(b) (\frac{\rho}{2})
(c) 2 ρ
(d) 4 ρ

Answer/Explanation
Answer: a
Explanation:
(a) Resistivity of the material depends only on the nature of material not dimensions.

2. A fuse wire repeatedly gets burnt when used with a good heater. It is advised to use a fuse wire of
   (a) more length
   (b) less radius
   (c) less length
   (d) more radius

Answer/Explanation
Answer: d
Explanation:
(d) In order to get the working of heater properly, fused wire of higher rating must be used

3. A battery of 10 volt carries 20,000 C of charge through a resistance of 20 Ω. The work done in 10 seconds is
   (a) 2 × 103 joule
   (b) 2 × 105joule
   (c) 2 × 104 joule
   (d) 2 × 102 joule

Answer/Explanation
Answer: b
Explanation:
(b) W= qV= 20000 × 10 = 2,00, 000 = 2 × 105 J

4. A boy records that 4000 joule of work is required to transfer 10 coulomb of charge between two points of a resistor of 50 Ω. The current passing through it is
   (a) 2 A
   (b) 4 A
   (c) 8 A
   (d) 16 A

Answer/Explanation
Answer: c
Explanation:
(c) Work done in transferring the charge
W= qV = qlR …….. (V = IR)

5. A cooler of 1500 W, 200 volt and a fan of 500 W, 200 volt are to be used from a household supply. The rating of fuse to be used is
   (a) 2.5 A
   (b) 5.0 A
   (c) 7.5 A
   (d) 10 A

Answer/Explanation
Answer: d
Explanation:
(d) Total power used, P = P1 + P1 = 1500 + 500 = 2000 W.
Current drawn from the supply,.

6. To get 2 Ω resistance using only 6 Ω resistors, the number of them required is
   (a) 2
   (b) 3
   (c) 4
   (d) 6

Answer/Explanation
Answer: b
Explanation:
(b) Three resistors of 2 Ω is required to get 6 Ω because resultant is more than individual so they all must be connected in series.

7. The effective resistance between A and b
   (a) 4Ω
   (b) 6Ω
   (c) May be 10 Ω
   (d) Must be 10 Ω

Answer/Explanation
Answer: a
Explanation:
(a) 6 Ω is shorted so effective resistance is 4 Ω.

8. Two devices are connected between two points say A and B in parallel. The physical quantity that will remain the same between the two points is
   (a) current
   (b) voltage
   (c) resistance
   (d) None of these

Answer/Explanation
Answer: b
Explanation:
(b) In parallel combination, voltage remains same across two points.

9. The least resistance obtained by using 2 Ω, 4 Ω, 1 Ω and 100 Ω is
   a) < 100 Ω (b) < 4 Ω (c) < 1 Ω (d) > 2 Ω

Answer/Explanation

Answer: cExplanation:
(c) In parallel combination, the equivalent resistance is smaller than the least resistance used in the circuit.

10. Two wires of same length and area, made of two materials of resistivity ρ1 and ρ2 are connected in parallel V to a source of potential. The equivalent resistivity for the same length and area is

Answer/Explanation
Answer: b
Explanation:
(b) Equivalent resistance in parallel combination is (\frac{1}{R_{P}}=\frac{1}{R_{1}}+\frac{1}{R_{2}})
For the same length and area of cross-section, R ∝ p (resistivity)

11. Calculate the current flows through the 10 Ω resistor in the following circuit.

MCQ Questions for Class 10 Science Electricity with Answers 5
(a) 1.2 A
(b) 0.6 A
(c) 0.2 A
(d) 2.0 A

Answer/Explanation
Answer: b
Explanation:
(b) In parallel, potential difference across each resistor will remain same. So, current through 10 Ω resistor
I = (\frac{V}{R}=\frac{6}{10}) = 0.6 A

12. Two resistors are connected in series gives an equivalent resistance of 10 Ω. When connected in parallel, gives 2.4 Ω. Then the individual resistance are
    (a) each of 5 Ω
    (b) 6 Ω and 4 Ω
    (c) 7 Ω and 4 Ω
    (d) 8 Ω and 2 Ω

Answer/Explanation
Answer: b
Explanation:
(b) In series, Rs = R1 + R2 = 10 Ω

13. If R1 and R2 be the resistance of the filament of 40 W and 60 W respectively operating 220 V, then
    (a) R1 < R2
    (b) R2 < R1
    (c) R1 = R2
    (d) R1 ≥ R2

Answer/Explanation
Answer: b
Explanation:
(b) Using power, P = (\frac{V^{2}}{R}) or R = (\frac{V^{2}}{P})
For the same voltage, R ∝ (\frac{1}{P})
More the power, lesser the resistance.
Accordingly, R2 < R1

14. A wire of length /, made of material resistivity ρ is cut into two equal parts. The resistivity of the two parts are equal to,
(a) ρ
(b) (\frac{\rho}{2})
(c) 2 ρ
(d) 4 ρ

Answer/Explanation
Answer: a
Explanation:
(a) Resistivity of the material depends only on the nature of material not dimensions.

15.What is the maximum resistance which can be made using five resistors each of 1/5 W? [NCERT Exemplar Problems]
(a) 1/5 Ω
(b) 10 Ω
(c) 5 Ω
(d) 1 Ω

Answer/Explanation
Answer: d
Explanation:
(d) Series combination provide the maximum resistance

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