Problem 1: A battery has an emf of 12.8 V and
supplies a current of 3.2A. What is the resistance of the circuit? How many coulombs leave the battery in 5 minutes?
Given emf = 12.8 V I = 3.2 A
t = 5 minutes = 5 * 60 = 300 seconds
Required Resistance of the circuit, R =?
Charge passed = Q =?
By Ohm’s law V = IR .
Put the values
For finding the amount of charge Q, we use the definition of current.
I = Q/t
Put values and simplify,