Several electric bulbs designed to be used on a 220 V electric supply line are rated 10 W each. How many bulbs can be connected in parallel with each other across the two wires of 220 V line if the maximum allowable current is 5 A ?

First we will calculate the resistance R of one bulb.

We know,

Therefore, resistance of one bulb is 4840

We will now calculate the total resistance of the circuit by using Ohm’s Law:

Thus, the total resistance of the circuit is 44.

Now, we need to find out the number of 4840 bulbs should be connected in parallel to obtain a total resistance of 44. Suppose the number of 4840 bulbs required is x. Then:

=110

Thus, 110 bulbs can be connected in parallel in this circuit.

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