A capacitor, an inductor and an electric bulb are connected in series to an AC supply of variable frequency. As the frequency of the supply is increased gradually, then the electric bulb is found to
A
increase in brightness
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
decrease in brightness
No worries! We‘ve got your back. Try BYJU‘S free classes today!
C
increase, reach a maximum and then decrease in brightness
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
D
show no change in brightness
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution
The correct option is D increase, reach a maximum and then decrease in brightness I=V
⎷R2+⎛⎝ωL−1ωC⎞⎠2
it is clear from te expression that as ω increases, (ωL−1ωC)2 decreases first then it starts increasing.
So the brightness increases first and then decreases.