NEET Solved Paper 2017 Question 20
Question: The resistance of a wire is ‘R’ ohm. If it is melted and stretched to ’n’ times its original length, its new resistance will be
Options:
A) $ \frac{R}{n^{2}} $
B) $ nR $
C) $ \frac{R}{n} $
D) $ n^{2}R $
Show Answer
Answer:
Correct Answer: D
Solution:
- $ \frac{R _2}{R _1}=\frac{l_2^{2}}{l_1^{2}} $ $ =\frac{n^{2}l_1^{2}}{l_1^{2}} $ $ \frac{R _2}{R _1}=n^{2} $ $ R _2=n^{2}R _1 $
