Question

1. A battery of EMF 6 V has an internal resistance of 0.15Ω. Calculate its terminal p.d. when delivering a current of 0.5 A.

2. State Ohm’s Law. Use this law to find the value of a Resistance of an electric circuit which has a Voltage of 220 V and a current of 20A

Answer 1

For question 1 :

• EMF = 6 Volt
• Internal resistance = 0.15 ohm
• Current in circuit = 0.5 A

Let terminal PD be V :

$V = E - (i \times r)$

$\implies V = 6 - (0.15 \times 0.5)$

$\implies V = 6 - 0.075$

$\implies V = 5.925 \: volt$

____________________________

Ohm's Law states that the potential drop (or voltage) across a conductor is directly proportional to the current $\rm pa{s}sing$ through it provided that all the physical conditions like temperature remains constant.

$V \propto \: i$

$\implies V = \: i \times r$

$\implies r = \dfrac{220}{20}$

$\implies r = 11 \: ohm$

So, resistance is 11 ohm