Several light bulbs, each of resistance 1.5 Ω, are connected in a series across a 120 V source of emf. If the current through the circuit is 2 A, how many light bulbs are there in the circuit?

Answer;

40 light bulbs

Explanation;

The total resistance of components or bulbs in series is given as the sum of resistance of all the components.

Thus; if there are bulbs in series each with a resistance of 1.5 Ω, the the total resistance will be; 1.5nΩ

From the ohms law;

V = IR, where V is the voltage, I is the current and R is the resistor.

Thus; R = V/i

R = 120/2

= 60 Ω

But, there are n bulbs each with 1.5 Ω; thus there are;

n = 60/1.5

= 40 Bulbs