Current Electricity Charging Discharging Of Capacitors Question 607

Question: The electromotive force of a primary cell is 2 volts. When it is short-circuited it gives a current of 4 amperes. Its internal resistance in ohms is

[MP PET 1995]

Options:

A) 0.5

B) 5.0

C) 2.0

D) 8.0

Show Answer

Answer:

Correct Answer: A

Solution:

$ E=V+ir $ After short-circuiting, $ V=0; $

Therefore $ r=\frac{E}{i}=\frac{2}{4}=0.5\Omega $