Question

A battery of internal resistance 1 Ω and emf of 12 volt connected to external resistance of 79 Ω.Calculate the power delivered by the battery to the circuit.

Answer 1

Answer:

P = 1.8 Watt

Explanation:

Electromotive Force (EMF)

It consists of a DC source ε with small internal resistance Ri. When it's connected to an external resistance Re a current i flows by the circuit whose value is given by:

$\displaystyle i =\frac{\varepsilon }{R_i+R_e}$

The internal resistance of the battery is Ri=1 ohm and its emf is ε=12 V. When connected to an external resistance of Re=79 ohm, the current is:

$\displaystyle i =\frac{12}{1+79}=\frac{12}{80}$

i = 0.15 A

The power delivered by the battery is:

P = ε.i

P = 12 V * 0.15 A

P = 1.8 Watt