Current Electricity Charging Discharging Of Capacitors Question 247

Question: A potentiometer wire has length 10 m and resistance $ 20,\Omega $ . A 2. 5 V battery of negligible internal resistance is connected across the wire with an $ 80,\Omega $ series resistance. The potential gradient on the wire will be

[KCET 1994]

Options:

A) $ 5\times {{10}^{-5}},V/mm $

B) $ 2.5\times {{10}^{-4}},V/cm $

C) $ 0.62\times {{10}^{-4}},V/mm $

D) $ 1\times {{10}^{-5}},V/mm $

Show Answer

Answer:

Correct Answer: A

Solution:

Potential gradient $ x=\frac{e}{(R+R _{h}+r)}\cdot \frac{R}{L} $

Therefore $ x=\frac{2.5}{(20+80+0)}\times \frac{20}{10}=5\times {{10}^{-5}}\frac{V}{mm} $