Question

At a given time, a house is supplied with 100A at 220V.How many
75 W, 220 V light bulbs could be switched on in the house at the same time
(if they are all connected in parallel)?​

Answer 1

Given that, current (I) = 100A, voltage (V) = 220V.

We have to find how many 75 W, 220 V light bulbs could be switched on in the house at the same time.

Also given that, all are connected in parallel. (Means, the voltage across the bulbs is same)

P = VI

P = 220(100)

P = 22000 W

Bulbs are rated at 75W per bulb.

Now,

Total number of bulbs = 22000/75 = 293.3

(Approx.) 293 bulbs could be switched on in the house at the same time.

Answer 2

In the given time,

Total current(I) = 100 A

Total voltage(V) = 220 V

Total power supplied(P) = VI

⇒P = 100*220

⇒P = 22000 W

rating of each bulb = 75 W, 220 V

Power consumed by each bulb = 75 W

Total number of bulbs that could be switched on in the house at the same time = 22000/75

       = 293.34

∴ So, total number of bulbs that could be switched on in the house at the same time are 293.