An A.C. source is connected to a resistive circuit. Which of the following is true?

Current and voltage are in same phase

Current leads ahead of voltage in phase

Current lags behind voltage in phase

Any of the above may be true depending upon the value of resistance

MEDIUM

12th CBSE

IMPORTANT

Earn 100

Plot a graph to show the variation of current with frequency of the ac source , explaining the nature of its variation for two different resistances $R_{1}$ and $R_{2}$ $(R_{1} < R_{2})$ at resonance.

Important Questions on Alternating Current

MEDIUM

12th CBSE

IMPORTANT

Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 7 - Alternating Current>Exercise>Q 1

a . c .

source of variable angular frequency

ω

is connected to

L - C - R

a series circuit. Which one of the following graphs in the figure represents the variation of current

I

with angular frequency

ω

HARD

12th CBSE

IMPORTANT

Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 7 - Alternating Current>Exercise>Q 2

What do you mean by resonant circuit. Give the required condition for series

L - C - R

resonant circuit derive the expression for its resonance frequency. Where this circuit is used?

EASY

12th CBSE

IMPORTANT

Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 7 - Alternating Current>Exercise>Q 3

An A.C. is represented by

e = 220 sin (100 π) t volt

and is applied over a resistance of 110 ohm. Calculate the heat produced in 7 minutes

MEDIUM

12th CBSE

IMPORTANT

Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 7 - Alternating Current>Exercise>Q 4

In an AC circuit the emf (

e

) and the current (

i

) at any instant are given respectively by,

E = E_{0} \sin (ω t)

and

I = I_{0} \sin (ω t - ϕ)

. The average power in the circuit over one cycle of AC is,

EASY

12th CBSE

IMPORTANT

Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 7 - Alternating Current>Exercise>Q 5

E_{0}

is the peak emf,

I_{0}

is the peak current and

ϕ

is the phase difference between them, then the average power dissipation in the circuit is

EASY

12th CBSE

IMPORTANT

Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 7 - Alternating Current>Exercise>Q 6

In an AC circuit the voltage applied is

E = E_{0} \sin ω t .

The resulting current in the circuit is

I = I_{0} \sin (ω t - \frac{π}{2})

. The power consumption in the circuit is given by

EASY

12th CBSE

IMPORTANT

Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 7 - Alternating Current>Exercise>Q 7

The average power generated in an inductor connected to an AC source is

HARD

12th CBSE

IMPORTANT

Physics Crash Course (Based on Revised Syllabus-2023)>Chapter 7 - Alternating Current>Exercise>Q 8

A LCR circuit with resistors, capacitors and inductors connected in series have the following values

R = 20 Ω, L = 1.5 H and C = 35 μF

. This combination of LCR series circuit has been connected to a variable frequency and a supply voltage of

200 V

ac supply. Calculate the average power that is transferred to the above connection in the entire cycle, when the supply frequency and the natural frequency are equal.

Plot a graph to show the variation of current with frequency of the ac source , explaining the nature of its variation for two different resistances R1 and R2 (R1< R2) at resonance.

Important Questions on Alternating Current

Learn and Prepare for any exam you want !

Plot a graph to show the variation of current with frequency of the ac source , explaining the nature of its variation for two different resistances $R_{1}$ and $R_{2}$ $(R_{1} < R_{2})$ at resonance.