When the resistance wire is passed through a die the cross-section area decreases by 1 % , the change in resistance of the wire is

Question

When the resistance wire is passed through a die the cross-section area decreases by 1 % , the change in resistance of the wire is (A) 1 % decrease (B) 1 % increase (C) 2 % decrease (D) 2 % increase

Tardigrade Admin · Accepted Answer

Resistance of a wire is R=(Ïl/A) (ÎR/R)=(Îl/l)-(ÎA/A)=1-(- 1)=2 %

Q. When the resistance wire is passed through a die the cross-section area decreases by $1%$ , the change in resistance of the wire is

$1%$ decrease

$1%$ increase

$2%$ decrease

$2%$ increase

Resistance of a wire is
$R = \frac{ρl}{A}$
$\frac{Δ R}{R} = \frac{Δ l}{l} - \frac{Δ A}{A} = 1 - (- 1) = 2%$

Q. When the resistance wire is passed through a die the cross-section area decreases by 1% , the change in resistance of the wire is

1% decrease

1% increase

2% decrease

2% increase