NCERT Solutions For Class 12 Physics Chapter 7: Alternating Current

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NCERT Solutions for Class 12 Physics Chapter 7 Alternating Current (AC) are provided in this article. Alternating current (AC) is an electric current which periodically reverses direction and changes its magnitude continuously with time in contrast to Direct Current (DC) which flows only in one direction. AC voltage is preferable in the circuits because it can be easily and efficiently converted into another voltage using a transformer.

Unit 4 Electromagnetic Induction and Alternating Currents along with Unit 3 Magnetic Effects of Current and Magnetism has a weightage of 17 marks in the CBSE Board examinations. The NCERT Solutions for Class 12 Physics Chapter 7 deals with concepts of alternating current, LC Oscillations, AC voltage applied to an inductor, capacitor, Power in Alternating Current, etc.

Download PDF: NCERT Solutions for Class 12 Physics Chapter 7

NCERT Solutions for Class 12 Physics Chapter 7

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Class 12 Physics Chapter 7 Topics Covered

Alternating Current refers to a changing voltage electric supply. It can be efficiently transformed from one form to another.
The charge and the electric current in a charged capacitor undergo LC Oscillations when it is connected to an inductor in the circuit.
RMS refers to the Root Mean Square of instantaneous current values. RMS value of alternating current is given by the direct current that flows through a resistance.

\(I_{rms} = \frac{I_0}{\sqrt{2}} = 0.707 I_0 \)

Wattless Current is when the average power consumed in an AC circuit corresponds to Zero.

The average power dissipated in AC circuit is given by:

P = VI cos ϕ

Here, V is the voltage applied, I is the current flowing, and ϕ is the phase difference between voltage and current

Power factor is a factor through which the apparent power should be multiplied in order to get active power.

cos θ = P/\|S\| = Actual power/Apparent power

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AC Generator	AC Voltage applied to an Inductor	AC Voltage Applied to a Capacitor
AC Voltage applied to LCR Circuit	AC Voltage applied to Resistor	Power in AC Circuit
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CBSE CLASS XII Related Questions

1.
Two heaters rated as \((P_1,V)\) and \((P_2,V)\) are connected in series across a dc source of \(V/2\) volt. The power consumed by the combination will be –
- \((P_1+P_2)\)
- \(\dfrac{P_1+P_2}{2}\)
- \(\dfrac{P_1P_2}{2(P_1+P_2)}\)
- \(\dfrac{P_1P_2}{4(P_1+P_2)}\)
View Solution
2.
Draw the number of scattered particles versus the scattering angle graph for scattering of alpha particles by a thin foil. Write two important conclusions that can be drawn from this plot.
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3.
If Bohr’s quantization postulate (angular momentum \( = \frac{nh}{2\pi} \)) is a basic law of nature, it should be equally valid for the case of planetary motion also. Why, then, do we never speak of quantization of orbits of planets around the Sun? Explain.
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4.
Photoemission of electrons occurs from a metal (\( \phi_0 = 1.96 \, \text{eV} \)) when light of frequency \( 6.4 \times 10^{14} \, \text{Hz} \) is incident on it. Calculate: Energy of a photon in the incident light, The maximum kinetic energy of the emitted electrons, and The stopping potential.
View Solution
5.
What is displacement current (\( i_d \))? Considering the case of charging of a capacitor, show that \( i_d = \varepsilon_0 \frac{d\Phi_E}{dt} \). What is the value of \( i_d \) for a conductor across which a constant voltage is applied?
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6.
Two small identical metallic balls having charges \( q \) and \( -2q \) are kept far at a separation \( r \). They are brought in contact and then separated at distance \( \frac{r}{2} \). Compared to the initial force \( F \), they will now:
- attract with a force \( \frac{F}{2} \)
- repel with a force \( \frac{F}{2} \)
- repel with a force \( F \)
- attract with a force \( F \)
View Solution

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NCERT Solutions For Class 12 Physics Chapter 7: Alternating Current

NCERT Solutions for Class 12 Physics Chapter 7

Previous Year Questions

Class 12 Physics Chapter 7 Topics Covered

CBSE CLASS XII Related Questions

1.
Two heaters rated as \((P_1,V)\) and \((P_2,V)\) are connected in series across a dc source of \(V/2\) volt. The power consumed by the combination will be –

2.
Draw the number of scattered particles versus the scattering angle graph for scattering of alpha particles by a thin foil. Write two important conclusions that can be drawn from this plot.

3.
If Bohr’s quantization postulate (angular momentum \( = \frac{nh}{2\pi} \)) is a basic law of nature, it should be equally valid for the case of planetary motion also. Why, then, do we never speak of quantization of orbits of planets around the Sun? Explain.

4.
Photoemission of electrons occurs from a metal (\( \phi_0 = 1.96 \, \text{eV} \)) when light of frequency \( 6.4 \times 10^{14} \, \text{Hz} \) is incident on it. Calculate: Energy of a photon in the incident light, The maximum kinetic energy of the emitted electrons, and The stopping potential.

5.
What is displacement current (\( i_d \))? Considering the case of charging of a capacitor, show that \( i_d = \varepsilon_0 \frac{d\Phi_E}{dt} \). What is the value of \( i_d \) for a conductor across which a constant voltage is applied?

6.
Two small identical metallic balls having charges \( q \) and \( -2q \) are kept far at a separation \( r \). They are brought in contact and then separated at distance \( \frac{r}{2} \). Compared to the initial force \( F \), they will now:

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NCERT Solutions For Class 12 Physics Chapter 7: Alternating Current

NCERT Solutions for Class 12 Physics Chapter 7

Previous Year Questions

Class 12 Physics Chapter 7 Topics Covered

CBSE CLASS XII Related Questions

1.Two heaters rated as \((P_1,V)\) and \((P_2,V)\) are connected in series across a dc source of \(V/2\) volt. The power consumed by the combination will be –

2. Draw the number of scattered particles versus the scattering angle graph for scattering of alpha particles by a thin foil. Write two important conclusions that can be drawn from this plot.

3. If Bohr’s quantization postulate (angular momentum \( = \frac{nh}{2\pi} \)) is a basic law of nature, it should be equally valid for the case of planetary motion also. Why, then, do we never speak of quantization of orbits of planets around the Sun? Explain.

4.Photoemission of electrons occurs from a metal (\( \phi_0 = 1.96 \, \text{eV} \)) when light of frequency \( 6.4 \times 10^{14} \, \text{Hz} \) is incident on it. Calculate: Energy of a photon in the incident light, The maximum kinetic energy of the emitted electrons, and The stopping potential.

5.What is displacement current (\( i_d \))? Considering the case of charging of a capacitor, show that \( i_d = \varepsilon_0 \frac{d\Phi_E}{dt} \). What is the value of \( i_d \) for a conductor across which a constant voltage is applied?

6.Two small identical metallic balls having charges \( q \) and \( -2q \) are kept far at a separation \( r \). They are brought in contact and then separated at distance \( \frac{r}{2} \). Compared to the initial force \( F \), they will now:

Similar Physics Concepts

Comments

SUBSCRIBE TO OUR NEWS LETTER

1.
Two heaters rated as \((P_1,V)\) and \((P_2,V)\) are connected in series across a dc source of \(V/2\) volt. The power consumed by the combination will be –

2.
Draw the number of scattered particles versus the scattering angle graph for scattering of alpha particles by a thin foil. Write two important conclusions that can be drawn from this plot.

3.
If Bohr’s quantization postulate (angular momentum \( = \frac{nh}{2\pi} \)) is a basic law of nature, it should be equally valid for the case of planetary motion also. Why, then, do we never speak of quantization of orbits of planets around the Sun? Explain.

4.
Photoemission of electrons occurs from a metal (\( \phi_0 = 1.96 \, \text{eV} \)) when light of frequency \( 6.4 \times 10^{14} \, \text{Hz} \) is incident on it. Calculate: Energy of a photon in the incident light, The maximum kinetic energy of the emitted electrons, and The stopping potential.

5.
What is displacement current (\( i_d \))? Considering the case of charging of a capacitor, show that \( i_d = \varepsilon_0 \frac{d\Phi_E}{dt} \). What is the value of \( i_d \) for a conductor across which a constant voltage is applied?

6.
Two small identical metallic balls having charges \( q \) and \( -2q \) are kept far at a separation \( r \). They are brought in contact and then separated at distance \( \frac{r}{2} \). Compared to the initial force \( F \), they will now: