Current Electricity Charging Discharging Of Capacitors Question 335
Question: The specific resistance of a wire is $ \rho $ , its volume is 3 $ m^{3} $ and its resistance is 3 ohms, then its length will be
[CPMT 1984]
Options:
A) $ \sqrt{\frac{1}{\rho }} $
B) $ \frac{3}{\sqrt{\rho }} $
C) $ \frac{1}{\rho }\sqrt{3} $
D) $ \rho \sqrt{\frac{1}{3}} $
Show Answer
Answer:
Correct Answer: B
Solution:
$ \text{Volume}=Al=3\Rightarrow A=\frac{3}{l} $
$ \text{Now} $
$ R=\rho \frac{l}{A}\Rightarrow 3=\frac{\rho \times l}{3/l}=\frac{\rho l^{2}}{3} $
$ \Rightarrow l^{2}=\frac{9}{\rho }=\frac{3}{\sqrt{\rho }} $
BETA
