Question

The maximum number of 40 W tube-lights connected in parallel which can safely be run from a 240 V supply with a 5 A fuse is ______.

Options

• 5

• 15

• 20

• 30

Answer 1

The maximum number of 40 W tube-lights connected in parallel which can safely be run from a 240 V supply with a 5 A fuse is 30.

Explanation:

Given: Voltage (V) = 240 V

Fuse rating (I_max) = 5 A

We know that,

P_total = V × I_max

⇒ P_total = 240 × 5

⇒ P_total = 1200 W

n = `P_"total"/P`

⇒ n = `1200/40`

⇒ n = 30