A battery of emf 15 V and internal resistance 3 ohm is connected to two resistors 3 ohm and 6 ohm connected in parallel. Find (a) the current through the battery (b) p.d. between the terminals of the battery (c) the current in 3 ohm resistor (d) the current in 6 ohm resistor.
A battery of emf 15 V and internal resistance 3 ohm is connected to two resistors 3 ohm and 6 ohm connected in parallel. Find (a) the current through the battery (b) p.d. between the terminals of the battery (c) the current in 3 ohm resistor (d) the current in 6 ohm resistor.

(a) According to the question,

When In parallel

1 / R = 1 / 3 + 1 / 6

1 / R = 1 / 2

R = 2 ohm

If

r = 3 W

ε = 15 V

ε = I (R + r)

15 = I (2 + 3)

I = 3 A

(b)  Now find V

R = 2 ohm

Using ohm’s law

V = IR

V = 3 × 2

V = 6 V

(c) V = 6 V

R = 3 ohm

I = V / R

I = 6 / 3

I = 2 A

(d) R = 6 ohm

V = 6 V

I = V / R

I = 6 / 6

I = 1 A