MEDIUM
12th ICSE
IMPORTANT
Earn 100

A bulb is connected in series with a variable capacitor. Will the bulb glow when this combination is connected to a DC supply/an AC supply? What would happen in each case, if the capacitance is reduced?

Important Questions on Alternating Current

EASY
12th ICSE
IMPORTANT
NOOTAN ISC PHYSICS Class 12 Part-1>Chapter 12 - Alternating Current>QUESTIONS>Q 34
For circuits used for transporting electric power, a low power factor implies large power loss in transmission. Explain.
EASY
12th ICSE
IMPORTANT
NOOTAN ISC PHYSICS Class 12 Part-1>Chapter 12 - Alternating Current>QUESTIONS>Q 35
Power factor can often be improved by introducing a capacitor of appropriate capacitance in the circuit. Explain.
EASY
12th ICSE
IMPORTANT
NOOTAN ISC PHYSICS Class 12 Part-1>Chapter 12 - Alternating Current>QUESTIONS>Q 36
How will you use a 100 V-50 W bulb on 200 V AC mains?
MEDIUM
12th ICSE
IMPORTANT
NOOTAN ISC PHYSICS Class 12 Part-1>Chapter 12 - Alternating Current>QUESTIONS>Q 37
Draw a labelled graph showing variation in impedance Z of a series L-C-R circuit with frequency f of alternating emf applied to it. What is the minimum value of this impedance?
I
EASY
12th ICSE
IMPORTANT
NOOTAN ISC PHYSICS Class 12 Part-1>Chapter 12 - Alternating Current>QUESTIONS>Q 38
State any two characteristics of resonance in an L-C-R series circuit.
HARD
12th ICSE
IMPORTANT
NOOTAN ISC PHYSICS Class 12 Part-1>Chapter 12 - Alternating Current>QUESTIONS>Q 1
What is an alternating current (AC)?
Show that the average value of AC over a complete cycle is zero while for a half-cycle it is 2I0/π, where I0 is the peak value of the current.
MEDIUM
12th ICSE
IMPORTANT
NOOTAN ISC PHYSICS Class 12 Part-1>Chapter 12 - Alternating Current>QUESTIONS>Q 2
Show that Irms=I0/2, where Irms is the root-mean-square value of the alternating current and I0 is its peak value. 
HARD
12th ICSE
IMPORTANT
NOOTAN ISC PHYSICS Class 12 Part-1>Chapter 12 - Alternating Current>QUESTIONS>Q 3
Show mathematically that in an AC circuit containing inductance only, the current lags behind the voltage by π/2.