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

Your Exam Success, Personally Taken Care Of

1:1 expert mentors customize learning to your strength and weaknesses – so you score higher in school , IIT JEE and NEET entrance exams.

An Intiative by Sri Chaitanya

Ammeter Reading-increases, Bulb brightness-increases

Ammeter Reading-increases, Bulb brightness-unchanged

Ammeter Reading-unchanged, Bulb brightness-unchanged

Ammeter Reading-decreases, Bulb brightness-unchanged

answer is D.

(Unlock A.I Detailed Solution for FREE)

Best Courses for You

JEE

NEET

Foundation JEE

Foundation NEET

CBSE

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 $R_{p} - \frac{R}{2} a n d I = 2 \frac{V}{R}$