The resistance of an incandescent lamp is

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

Question

(C) The resistance $R$ of a metallic conductor is given by $R = \frac{ml}{ne^2 	au A}$,where $	au$ is the relaxation time.As the temperature $T$ inc

Vedclass · Accepted Answer

Greater when switched on

Vedclass · Answer

(C) The resistance $R$ of a metallic conductor is given by $R = \frac{ml}{ne^2 	au A}$,where $	au$ is the relaxation time.As the temperature $T$ increases,the frequency of collisions between electrons and ions increases,which causes the relaxation time $	au$ to decrease.Since $R \propto \frac{1}{	au}$,a decrease in $	au$ leads to an increase in resistance $R$.When an incandescent lamp is switched on,the filament heats up,causing its temperature to rise. Consequently,the resistance of the lamp is greater when it is switched on compared to when it is switched off.

Similar Questions

Wires $P$ and $Q$ have the same resistance at ordinary (room) temperature. When heated,the resistance of $P$ increases and that of $Q$ decreases. We conclude that:

$A$ cylindrical wire is stretched such that its length is doubled but its volume remains constant. The resistance of the wire will become.......

What is resistivity? Write its unit. On what factors does resistivity depend?

The conductivity of a superconductor is.......

$A$ copper wire is stretched to increase its length by $0.1\%$. What is the percentage increase in the resistance of the wire (in $\%$)?

Vedclass Test Series

Exam Paper Generator

Online Exam Module