Several electric bulbs designed to be used on a 220 V electric supply line, are rated 10 W

Explanation:
Here we are going to use the concept of ohm’s law.
Power of each bulb is P=10W.
Voltage of the electric supply line is V = 220V.
Hence Resistance of each bulb is
R = V2P = 4840
Let there are ‘n’ number of bulbs
According to the question, ‘n’ number of bulbs are in parallel connection. So equivalent resistance of the parallel combination is
1Req=14840+14840+14840 + ...........n times
 Req = 4840n
Req = VI
 4840n=VI
 4840n=2205 ( maximum allowable current, I = 5 A)
 n=110

Final Answer:
110 lamps can be connected in parallel with each other across the two wires of 220 V line if the maximum allowable current is 5 A