Current Electricity Charging Discharging Of Capacitors Question 234

Question: A resistance of $ 4,\Omega $ and a wire of length 5 metres and resistance $ 5,\Omega $ are joined in series and connected to a cell of e.m.f. 10 V and internal resistance $ 1,\Omega $ . A parallel combination of two identical cells is balanced across 300 cm of the wire. The e.m.f. E of each cell is

[MP PMT 1997]

Options:

A) 1.5 V

B) 3.0 V

C) 0.67 V

D) 1.33 V

Show Answer

Answer:

Correct Answer: B

Solution:

$ E=x,l=\frac{V}{l}=\frac{iR}{L}\times l $

Therefore $ E=\frac{e}{(R+R _{h}+r)}\times \frac{R}{L}\times l $

Therefore $ E=\frac{10}{(5+4+1)}\times \frac{5}{5}\times 3=3,V $