Question

2.5.

Make a prediction on what will happen if you will double (a) the length of the wire and (b) the cross-sectional area of the wire. Then, support your answer by solving for the resistance in each of the given situation.

Answer 1

Resistance is given by-

$R=\dfrac{\rho l}{A}$

(i) When length become dobled than new resistance,

$R'=\dfrac{\rho \times 2l}{A}=2R$

Resistance become doubled.

(ii) When cross sectional are become doubled-

$R'=\dfrac{\rho l}{2A}=\dfrac{R}{2}$

Resistance become half.