NCERT Solutions For Class 12 Physics Chapter 9: Ray Optics and Optical Instruments

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NCERT Solutions for Class 12 Physics Chapter 9 Ray Optics and Optical Instruments are provided in this article. Optics helps us study the properties and behaviour of light. In Ray Optics, the light travels in a straight line stating that there is an image for each and every object. The optical devices made utilising reflecting and refracting properties of lenses, mirrors and prisms known as Optical instruments.

Class 12 Physics Chapter 9 is a part of Unit 6 Optics which along with Unit 5 Electromagnetic Waves has a weightage of 18 marks in the CBSE Class 12 Board exam. The NCERT Solutions for Class 12 Physics Chapter 9 covers concepts of refraction, Snell’s Law, and total internal reflection

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NCERT Solutions for Class 12 Physics Chapter 9

NCERT Solutions

Class 12 Physics Chapter 9 – Important Topics Covered

Ray Optics is the branch of physics that deals with the behaviour of light as a ray which travels in a straight line.

Light always travels in a straight line. It does not require any medium to travel

Reflection is the phenomenon wherein light changes its path without any change in the medium.

Laws of Reflection

The angle of incidence, represented as i is equal to the angle of reflection, represented as r.
∠i = ∠r.
The incident ray, the reflected ray and the normal to the reflecting surface at the incidence point, all lie in the same plane.

The mirror formula represents a relation between the focal length of the mirror and the distances of objects and images from the mirror.

${1 \over v} + {1 \over u} = {1 \over f} $

Linear Magnification: The ratio of the size of the image that is formed by a spherical mirror I to the size of the object O is known as linear magnification.

$m={I \over O}={-v \over u}$

Refraction is the phenomenon of change in the path of light as it goes from one medium to another.

Laws of Refraction

The incident ray, refracted ray and the normal to the refracting surface at the point of incidence, all lie in the same plane.
The ratio of the sin of the angle of incidence to the sin of the angle of refraction is constant for any two given mediums. This constant is the relative refractive index.

n = sin i/sin r (Snell’s law)

where, n is the refractive index of the second medium when first medium is air.

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CBSE CLASS XII Related Questions

1.
Consider the nuclear reaction $ X \to Y + Z $. Let $ M_x $, $ M_y $, and $ M_z $ be the masses of the three nuclei X, Y, and Z respectively. Then which of the following relations hold true?

$ (M_x - M_z)<M_y $
$ (M_x - M_y)<M_z $
$ M_x>(M_y + M_z) $
$ M_x<(M_y + M_z) $

View Solution

2.
A circular coil of 100 turns and radius $\left(\frac{10}{\sqrt{\pi}}\right)$ cm carrying current of $5.0\,\text{A}$ is suspended vertically in a uniform horizontal magnetic field of $2.0\,\text{T}$. The field makes an angle $30^\circ$ with the normal to the coil. Calculate:
(I) the magnetic dipole moment of the coil, and
(II) the magnitude of the counter torque that must be applied to prevent the coil from turning.

View Solution

3.
Determine the current in the $ 3 \, \Omega $ branch of a Wheatstone Bridge in the circuit shown in the figure.

View Solution

4.
A current of $4.0\,\text{A}$ flows through a wire of length $1\,\text{m}$ and cross-sectional area $1.0\,\text{mm}^2$, when a potential difference of $2\,\text{V}$ is applied across its ends. Calculate the resistivity of the material of the wire.

View Solution

5.
A ray of light MN is incident normally on the face corresponding with side AB of a prism with an isosceles right-angled triangular base ABC. Trace the path of the ray as it passes through the prism when the refractive index of the prism material is (i) $\sqrt{2}$, and (ii) $\sqrt{3}$.

View Solution

6.
The resistance of a metal wire at $20^\circ\text{C}$ is $1.05\,\Omega$ and at $100^\circ\text{C}$ is $1.38\,\Omega$. Determine the temperature coefficient of resistivity of this metal.

View Solution

NCERT Solutions For Class 12 Physics Chapter 9: Ray Optics and Optical Instruments

NCERT Solutions for Class 12 Physics Chapter 9

Class 12 Physics Chapter 9 – Important Topics Covered

CBSE CLASS XII Related Questions

1.
Consider the nuclear reaction \( X \to Y + Z \). Let \( M_x \), \( M_y \), and \( M_z \) be the masses of the three nuclei X, Y, and Z respectively. Then which of the following relations hold true?

3.
Determine the current in the \( 3 \, \Omega \) branch of a Wheatstone Bridge in the circuit shown in the figure.

4.
A current of \(4.0\,\text{A}\) flows through a wire of length \(1\,\text{m}\) and cross-sectional area \(1.0\,\text{mm}^2\), when a potential difference of \(2\,\text{V}\) is applied across its ends. Calculate the resistivity of the material of the wire.

5.
A ray of light MN is incident normally on the face corresponding with side AB of a prism with an isosceles right-angled triangular base ABC. Trace the path of the ray as it passes through the prism when the refractive index of the prism material is (i) $\sqrt{2}$, and (ii) $\sqrt{3}$.

6.
The resistance of a metal wire at \(20^\circ\text{C}\) is \(1.05\,\Omega\) and at \(100^\circ\text{C}\) is \(1.38\,\Omega\). Determine the temperature coefficient of resistivity of this metal.

Similar Physics Concepts

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NCERT Solutions For Class 12 Physics Chapter 9: Ray Optics and Optical Instruments

NCERT Solutions for Class 12 Physics Chapter 9

Class 12 Physics Chapter 9 – Important Topics Covered

CBSE CLASS XII Related Questions

1.Consider the nuclear reaction \( X \to Y + Z \). Let \( M_x \), \( M_y \), and \( M_z \) be the masses of the three nuclei X, Y, and Z respectively. Then which of the following relations hold true?

3. Determine the current in the \( 3 \, \Omega \) branch of a Wheatstone Bridge in the circuit shown in the figure.

4.A current of \(4.0\,\text{A}\) flows through a wire of length \(1\,\text{m}\) and cross-sectional area \(1.0\,\text{mm}^2\), when a potential difference of \(2\,\text{V}\) is applied across its ends. Calculate the resistivity of the material of the wire.

5.A ray of light MN is incident normally on the face corresponding with side AB of a prism with an isosceles right-angled triangular base ABC. Trace the path of the ray as it passes through the prism when the refractive index of the prism material is (i) $\sqrt{2}$, and (ii) $\sqrt{3}$.

6.The resistance of a metal wire at \(20^\circ\text{C}\) is \(1.05\,\Omega\) and at \(100^\circ\text{C}\) is \(1.38\,\Omega\). Determine the temperature coefficient of resistivity of this metal.

Similar Physics Concepts

Comments

SUBSCRIBE TO OUR NEWS LETTER

1.
Consider the nuclear reaction \( X \to Y + Z \). Let \( M_x \), \( M_y \), and \( M_z \) be the masses of the three nuclei X, Y, and Z respectively. Then which of the following relations hold true?

3.
Determine the current in the \( 3 \, \Omega \) branch of a Wheatstone Bridge in the circuit shown in the figure.

4.
A current of \(4.0\,\text{A}\) flows through a wire of length \(1\,\text{m}\) and cross-sectional area \(1.0\,\text{mm}^2\), when a potential difference of \(2\,\text{V}\) is applied across its ends. Calculate the resistivity of the material of the wire.

5.
A ray of light MN is incident normally on the face corresponding with side AB of a prism with an isosceles right-angled triangular base ABC. Trace the path of the ray as it passes through the prism when the refractive index of the prism material is (i) $\sqrt{2}$, and (ii) $\sqrt{3}$.

6.
The resistance of a metal wire at \(20^\circ\text{C}\) is \(1.05\,\Omega\) and at \(100^\circ\text{C}\) is \(1.38\,\Omega\). Determine the temperature coefficient of resistivity of this metal.