Question

If two bulbs are connected in parallel and one bulb blows out, what happens to the other bulb?

(a) The other bulb blows out as well

(b) The other bulb continues to glow with the same brightness

(c) The other bulb glows with increased brightness

(d) The other bulb stops glowing

I have been asked this question in an internship interview.

This interesting question is from Parallel Networks in chapter Simple DC Networks of Basic Electrical Engineering

Answer 1

Right answer is (b) The other bulb continues to glow with the same brightness

To elaborate: If one bulb blows out, it acts as an open circuit. Current does not flow in that branch but it continues to flow in the other branch of the parallel circuit. Hence the other bulb continues to glow. Also the voltage across other bulb remains the same due to which power delivered to it remains the same so it continues to glow with the same brightness.