Current Electricity Charging Discharging Of Capacitors Question 412
Question: A wire of radius r has resistance R. If it is stretched to a radius of $ \frac{3r}{4} $ , its resistance becomes
[BHU 2002]
Options:
A) $ \frac{9R}{16} $
B) $ \frac{16R}{9} $
C) $ \frac{81R}{256} $
D) $ \frac{256R}{81} $
Show Answer
Answer:
Correct Answer: D
Solution:
$ \frac{R _{1}}{R _{2}}={{( \frac{r _{2}}{r _{1}} )}^{4}} $
Therefore $ \frac{R}{R _{2}}={{( \frac{3r/4}{r} )}^{4}}=\frac{81}{256}=R _{2}=\frac{256}{81}R $
BETA
