Two fuse wires A and B

PHYSICS · Single correct · A Level · Physics · Electricity · Electricity

Problem

Two fuse wires A and B, each

5\,\text{cm}

long and made of the same material, have cross-sectional areas

0.02\,\text{mm}^2

and

0.05\,\text{mm}^2

respectively. The same steady current of

3\,\text{A}

passes through both wires for the same time. What is the ratio of heat produced in wire A to that in wire B? (a)

25:4

(b)

2:5

(c)

5:2

(d)

1:1

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