# How Does the Resistance of a Wire Change When: Its Diameter is Tripled? - Science

How does the resistance of a wire change when:

its diameter is tripled?

#### Solution

Resistance,

R=l/A

where l = length of  wire
A= area of cross-section of the wire

When the diameter is tripled, d' = 3Radius, r' = 3r

Area of cross-section, A=Api^2=A(3pi)^2=9Api^2=9A

Thus, the area of cross-section will become nine times.

Then the new resistance,

R'=l/A

R'=l/9A

R'=R/9

Thus, the resistance will be reduced by nine times.

Is there an error in this question or solution?

#### APPEARS IN

Lakhmir Singh Class 10 Physics (Science)
Chapter 1 Electricity
Q 22.2
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