Current Electricity Charging Discharging Of Capacitors Question 252
Question: The resistance of 10 metre long potentiometer wire is 1ohm/meter. A cell of e.m.f. 2.2 volts and a high resistance box are connected in series to this wire. The value of resistance taken from resistance box for getting potential gradient of 2.2 millivolt/metre will be
[RPET 1997]
Options:
A) $ 790,\Omega $
B) $ 810,\Omega $
C) $ 990,\Omega $
D) $ 1000,\Omega $
Show Answer
Answer:
Correct Answer: C
Solution:
Potential gradient $ x=\frac{V}{L}=\frac{e}{(R+R _{h}+r)}\cdot \frac{R}{L} $
Therefore $ 2.2\times {{10}^{-3}}=\frac{2.2}{(10+R _{h})}\times 1 $
Therefore $ {R}’=990,\Omega $
BETA
