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.
Assertion (A) : All atoms have a net magnetic moment. Reason (R) : A current loop does not always behave as a magnetic dipole.

Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
Assertion (A) is true, but Reason (R) is false.
Both Assertion (A) and Reason (R) are false.

View Solution

2.
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?

View Solution

3.
If both the number of protons and the neutrons are conserved in each nuclear reaction, in what way is mass converted into energy (or vice versa) in a nuclear reaction? Explain.

View Solution

4.
Assertion (A) : The mass of a nucleus is less than the sum of the masses of the constituent nucleons. Reason (R) : Energy is absorbed when the nucleons are bound together to form a nucleus.

Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).
Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).
Assertion (A) is true, but Reason (R) is false.
Both Assertion (A) and Reason (R) are false.

View Solution

5.
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

6.
The figure shows three point charges kept at the vertices of triangle ABC. The net electric field, due to this system of charges, at the midpoint M of base BC will be:

\( \frac{q}{4 \pi \epsilon_0 l^2} \) pointing along MA
\( \frac{q}{\pi \epsilon_0 l^2} \) pointing along AM
\( \frac{q}{2 \pi \epsilon_0 l^2} \) pointing along AM
Zero

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.
Assertion (A) : All atoms have a net magnetic moment. Reason (R) : A current loop does not always behave as a magnetic dipole.

2.
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?

3.
If both the number of protons and the neutrons are conserved in each nuclear reaction, in what way is mass converted into energy (or vice versa) in a nuclear reaction? Explain.

4.
Assertion (A) : The mass of a nucleus is less than the sum of the masses of the constituent nucleons. Reason (R) : Energy is absorbed when the nucleons are bound together to form a nucleus.

5.
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:

6.
The figure shows three point charges kept at the vertices of triangle ABC. The net electric field, due to this system of charges, at the midpoint M of base BC will be:

Similar Physics Concepts

Comments

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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.Assertion (A) : All atoms have a net magnetic moment. Reason (R) : A current loop does not always behave as a magnetic dipole.

2.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?

3. If both the number of protons and the neutrons are conserved in each nuclear reaction, in what way is mass converted into energy (or vice versa) in a nuclear reaction? Explain.

4.Assertion (A) : The mass of a nucleus is less than the sum of the masses of the constituent nucleons. Reason (R) : Energy is absorbed when the nucleons are bound together to form a nucleus.

5.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:

6.The figure shows three point charges kept at the vertices of triangle ABC. The net electric field, due to this system of charges, at the midpoint M of base BC will be:

Similar Physics Concepts

Comments

SUBSCRIBE TO OUR NEWS LETTER

1.
Assertion (A) : All atoms have a net magnetic moment. Reason (R) : A current loop does not always behave as a magnetic dipole.

2.
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?

3.
If both the number of protons and the neutrons are conserved in each nuclear reaction, in what way is mass converted into energy (or vice versa) in a nuclear reaction? Explain.

4.
Assertion (A) : The mass of a nucleus is less than the sum of the masses of the constituent nucleons. Reason (R) : Energy is absorbed when the nucleons are bound together to form a nucleus.

5.
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:

6.
The figure shows three point charges kept at the vertices of triangle ABC. The net electric field, due to this system of charges, at the midpoint M of base BC will be: