If a wire of resistance R is melted and recas | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(A) The resistance of a wire is given by the formula $R = \rho \frac{L}{A}$,where $\rho$ is the resistivity,$L$ is the length,and $A$ is the cross-sec

Vedclass · Accepted Answer

$R / 4$

Vedclass · Answer

(A) The resistance of a wire is given by the formula $R = ho \frac{L}{A}$,where $ho$ is the resistivity,$L$ is the length,and $A$ is the cross-sectional area.When the wire is melted and recast to half its length $(L' = L / 2)$,its volume remains constant.Since $V = A 	imes L$,we have $A 	imes L = A' 	imes L'$.Substituting $L' = L / 2$,we get $A 	imes L = A' 	imes (L / 2)$,which implies $A' = 2A$.The new resistance $R'$ is given by $R' = ho \frac{L'}{A'}$.Substituting the new values: $R' = ho \frac{L / 2}{2A} = \frac{1}{4} 	imes ho \frac{L}{A}$.Therefore,$R' = R / 4$.

If a wire of resistance $R$ is melted and recast to half of its length,then the new resistance of the wire will be

Similar Questions

Name a few practical applications of the heating effect of current.

$A$ hot plate of an electric oven connected to a $220 \ V$ line has two resistors $A$ and $B$ each of $22 \ \Omega$ resistance. These resistors may be used separately,in series,or in parallel. Find the current flowing in all the three cases.

Calculate the number of electrons that would flow per second through the cross-section of a wire when $1 \, A$ current flows in it.

Give two practical applications of the heating effect of current.

Define current,give its mathematical expression. What is its $SI$ unit?

Vedclass Test Series

Exam Paper Generator

Online Exam Module