Current Electricity Charging Discharging Of Capacitors Question 407
Question: The resistance of an incandescent lamp is
[KCET 2002]
Options:
A) Greater when switched off
B) Smaller when switched on
C) Greater when switched on
D) The same whether it is switched off or switched on
Show Answer
Answer:
Correct Answer: C
Solution:
$ R\propto \frac{1}{\tau }; $ where $ \tau $ = Relaxation time. When lamp is switched on, temperature of filament increase, hence $ \tau $ decrease so R increases
BETA
