Three similar light bulbs are connected to a constant voltage dc supply as shown in figure. Each bulb operates at normal brightness and the ammeter (of negligible resistance) registers a steady current. The filament of one of the bulbs breaks. What happens to the ammeter reading and to the brightness of the remaining bulbs?

see full answer

Talk to JEE/NEET 2025 Toppers - Learn What Actually Works!

Real Strategies. Real People. Real Success Stories - Just 1 call away

An Intiative by Sri Chaitanya

Ammeter Reading-increases, Bulb brightness-increases

Ammeter Reading-decreases, Bulb brightness-unchanged

Ammeter Reading-increases, Bulb brightness-unchanged

Ammeter Reading-unchanged, Bulb brightness-unchanged

answer is D.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

Suppose V is the voltage of the supply and R is the resistance of each bulb. Now, $S_{1} n o r R_{p} = R / 3$ and current in ammeter is $I = V / R_{p} = 3 V / R,$ provided all three bulbs are working properly. If one bulb has broken down, then $R_{p} - \frac{R}{2} a n d I = 2 \frac{V}{R}$