Current Electricity Charging Discharging Of Capacitors Question 407
Question: The resistance of an incandescent lamp is
[KCET 2002]
Options:
A) Greater when switched on
B) Smaller when switched on
C) Greater when activated
D) It is 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
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