The resistance of hot tungsten filament is about 10 times the cold resistance. What will be the resistance of 100 W and 200 V lamp when not in use?
- (A)✓ Correct
- (B)
- (C)
- (D)
Answer: (A)
Solution
In use the filament is hot, with resistance . Since the hot resistance is about ten times the cold one, when the lamp is off its resistance is .
JEE Main · 2005 · 08 May 2005 · Offline · Single correct option