How many sixty watt (60 W) bulbs may be safely used in a 240-V supply with 4-ampere fuse?

To determine the number of 60 W bulbs that can be safely used, we first calculate the total power capacity of the circuit. Using the power formula P = V × I, where V is the supply voltage (240 V) and I is the fuse rating (4 A), the maximum allowable power is 240 V × 4 A = 960 W [t1][t6]. Each bulb is rated at 60 W. The current drawn by a single 60 W bulb at 240 V is calculated as I = P/V, which is 60 W / 240 V = 0.25 A [t1][t6]. To find the maximum number of bulbs, we divide the total available power by the power of one bulb: 960 W / 60 W = 16 bulbs. Alternatively, dividing the total fuse current by the current per bulb (4 A / 0.25 A) also yields 16 [t1]. Thus, 16 bulbs can be safely operated without exceeding the 4-ampere fuse limit.