The resistance of the filament of an electric bulb changes with temperature. If an electric bulb rated 220 volt and 100 watt is connected 
volt sources, then the actual power would be
A
B
C
Between 
watt and 100 watt
watt and 100 watt
D
Between 
and 
watt
and watt
Text Solution
Verified by ExpertsThe correct answer is:
D
and 
⇒ ⇒ 
Here R 2 < R 1
(because voltage decreases from 220 V → → 220 × × 0.8 V
It means heat produced → → decreases)
So 
⇒ ⇒ 
⇒ ⇒ 
Also 
Since 
(we expect)
So 
⇒ ⇒ 
Hence the actual power would be between 
and (100 × × 0.8) W
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