Question

When a resistance of 2 ohm placed across the terminals of a
battery, the current is 0.5A, when the resistance across terminals
is 5 ohm the current is
o 25 A. Calculate the emt of the battery.​

Answer 1

Explanation:

Given: A battery of emf 10V and internal resistance 3Ω is connected to a resistor. The current in the circuit is 0.5A

To find the terminal voltage of the battery when the circuit is closed

Solution:

Emf of the battery, E=10V

Internal resistance of the battery, r=3Ω

Current in the circuit, I=0.5A

Resistance of the resistor = R

The relation for current using Ohm's law is,

I=

R+r

E

⟹R+r=

I

E

⟹R+r=

0.5

10

⟹R=20−3=17Ω

Terminal voltage of the resistor = V

According to Ohm's Law,

V=IR

⟹V=0.5×17

⟹V=8.5V

Therefore, the resistance of the resistor is 17Ω and the terminal voltage is 8.5V