CBSE Class 10 Science 2020 · Paper 31/4/1 · Question 29(b)

Electricity 5 marks Medium

Two identical resistors, each of resistance

15 Ω

, are connected in

(i)series, and
(ii)parallel, in turn to a battery of 6 V. Calculate the ratio of the power consumed in the combination of resistors in each case.

Answer

The power consumed in series and in parallel is 1.2 W and 4.8 W, so the ratio is $P_{1} : P_{2} = 1 : 4$ .

(i) In series:

R_{s} = 15 + 15 = 30 Ω

I = \frac{6}{30} = 0.2

A, so

P_{1} = V I = 6 \times 0.2 = 1.2

W. (ii) In parallel:

R_{p} = \frac{15 \times 15}{15 + 15} = 7.5 Ω

I = \frac{6}{7.5} = 0.8

A, so

P_{2} = V I = 6 \times 0.8 = 4.8

W. Ratio of the powers consumed:

P_{1} : P_{2} = 1.2 : 4.8 = 1 : 4

🔒 Step-by-step solution