0
You visited us 0 times! Enjoying our articles? Unlock Full Access!
Question

# Two bulbs 40W and 60W and rated voltage 240V are connected in series across a potential difference of 420V. Which bulb will work at above its rated voltage?

A
40W bulb
No worries! Weâ€˜ve got your back. Try BYJUâ€˜S free classes today!
B
60W bulb
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C
Both will work
No worries! Weâ€˜ve got your back. Try BYJUâ€˜S free classes today!
D
None of these
No worries! Weâ€˜ve got your back. Try BYJUâ€˜S free classes today!
Open in App
Solution

## The correct option is D 60W bulbMaximum current flowing through a bulb I=PVFor bulb of 40 W :Maximum current I1=40240=0.167 AResistance of bulb, R1=(240)240=1440ΩFor bulb of 60 W :Maximum current I2=60240=0.25 AResistance of bulb, R2=(240)260=960ΩNow both the bulbs are connected in series :Total resistance of the circuit R=960+1440=2400ΩThus current flowing through the circuit I=4202400=0.175 AAs current flowing through the circuit is greater than the maximum current that flows through bulb of 40 W, thus this bulb will not work but bulb of 60 W does.

Suggest Corrections
0
Join BYJU'S Learning Program
Related Videos
Series RLC
PHYSICS
Watch in App
Explore more
Join BYJU'S Learning Program