light

Q1) if the angle of incidence formed on a plane mirror is 63 , what will be the measure of the angle of reflection?

Ans: According to the second law of reflection, if the angle of incidence is 63, then the angle of reflection will be 63.

Q2) How will the light falling on a surface of plane mirror travel?

Ans:  when a beam of light strike a smooth surface like that of a mirror, the rays are reflected . the reflected rays are also parallel to each other.

Q3) how will the light falling on a rough surface of a rock travel?

Ans: The parallel rays of light after striking a rough surface scatter in different directions.

Q4) Define refraction ?

Ans: The path of light changes as it passes from one medium to another. The path of the ray bends. This is known as refraction.

Q5) what is dispersion of light?

Ans: The splitting of white light into its components colours is called dispersion of light.

Q6) On which layer of the human eye is the image formed?

Ans: The image is formed on the retina

Q7) where in the human eye is the aqueous humor found?

Ans: Between the cornea and the iris is a liquid called the aqueous humor.

Q8) what type of lens is used to correct the defect of nearsightedness?

Ans: Concave lens.

Q9) explain reflection of light?

Ans: When light bounces after striking a surface, we say the light has reflected. This known as reflection of light.

Q10) what is the point of incidence?

Ans: The point at which the incident ray strikes the reflecting surface is called point of incidence.

Q11) what is virtual image?

Ans: The image which is not formed by actual rays of light , it cannot be captured on a screen. Such an image is known as a virtual image.

Q12) Differentiate between regular and irregular reflection.

Ans: When a beam of light strikes a smooth surface like that of a mirror, the rays are reflected. The reflected rays are also parallel to each other. Such a reflection is called specular  or regular reflection.

The parallel rays of light after striking a rough surface scatter in different directions, this type of reflection is known As diffuse or irregular reflection.

Q13) List any two features of an image formed by a plane mirror.

Ans: The image is upright and virtual

·       The image is laterally inverted.

Q14) List the three layers of human eye?

Ans: The human eye has three layers:

 The outer most sclera, chroid and the inner retina.

Q15) Explain the first law of reflection with a diagram?

Ans: The incident ray, the normal drawn at the point of incident and the reflected ray all lie in the same plane.

Q16) how is an image in a plane mirror?

Ans:  When light rays from an object fall on the surface of the plane mirror, they get reflected back. These reflected rays meet at a point when extended backward, the image is formed at this point. As the image is not formed by actual rays of light, it cannot be captured on a screen, such an image is known as a virtual image.

Q17) what is farsightedness? How can it be corrected?

Ans: A person with farsightedness ( hyperopia) has difficulty seeing objects that are near , this is because the light rays from a closer distance become focused behind the retina, this is caused by an eye ball that is too short.

This is corrected with a convex lens, which converges light and focuses it on the retina.

Q18) list the causes of blindness. Explain any one of them?

Ans: As a person ages, the eye sight is affected , most often the retina degenerates. As a result, the person has blurred vision and has difficulty in reading.

-      Diabetes, Cataract and Glaucoma are other causes of blindness in elderly people.

Glaucoma is a condition in which the pressure within the eye is increased due to an excess of aqueous humor liquid. It occurs in elderly people and can be managed with medicines and surgery.