Q: 1. What is the difference between regular and diffused reflection?

Regular Reflection occurs on a smooth surface, where parallel light rays reflect in a specific direction, forming a clear image (e.g., plane mirror). Diffused Reflection occurs on a rough surface, where parallel light rays scatter in different directions, not forming a clear image (e.g., paper surface).

Q: 2. What is the law of reflection?

The laws of reflection state that: a) The incident ray, the reflected ray, and the normal to the surface of reflection all lie in the same plane. b) The angle of incidence is always equal to the angle of reflection.

Q: 3. What are the laws of refraction?

The laws of refraction state that: a) The incident ray, refracted ray, and normal all lie in the same plane. b) The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant, known as Snell’s Law : n=sin⁡(i) /sin(⁡r) where n is the refractive index.

Q: 4. What is the refractive index?

The refractive index (n) of a medium is the ratio of the speed of light in a vacuum to the speed of light in that medium. n=c/v where: c = speed of light in vacuum v = speed of light in the medium

Q: 6. What is the difference between concave and convex mirrors?

Concave Mirror : A mirror with a reflecting surface curved inward, used in torches, headlights, and shaving mirrors. Convex Mirror : A mirror with a reflecting surface curved outward, used in rear-view mirrors of vehicles.

Q: 7. What are the uses of concave and convex lenses?

Convex Lens : Used in magnifying glasses, cameras, and human eyes to converge light. Concave Lens : Used in spectacles for myopia (nearsightedness) and in laser devices to diverge light.

Q: 9. Why does a pencil appear bent in water?

A pencil appears bent in water due to refraction —light changes speed and direction as it moves from water to air.

Question 1

1. What is the difference between regular and diffused reflection?

Accepted Answer

Regular Reflection occurs on a smooth surface, where parallel light rays reflect in a specific direction, forming a clear image (e.g., plane mirror).
Diffused Reflection occurs on a rough surface, where parallel light rays scatter in different directions, not forming a clear image (e.g., paper surface).

Question 2

2. What is the law of reflection?

Accepted Answer

The laws of reflection state that:
a) The incident ray, the reflected ray, and the normal to the surface of reflection all lie in the same plane.
b) The angle of incidence is always equal to the angle of reflection.

Question 3

3. What are the laws of refraction?

Accepted Answer

The laws of refraction state that:
a) The incident ray, refracted ray, and normal all lie in the same plane.
b) The ratio of the sine of the angle of incidence to the sine of the angle of refraction is constant, known as Snell’s Law:
n=sin⁡(i) /sin(⁡r)
where n is the refractive index.

Question 4

4. What is the refractive index?

Accepted Answer

The refractive index (n) of a medium is the ratio of the speed of light in a vacuum to the speed of light in that medium.
n=c/v
where:
c = speed of light in vacuum
v = speed of light in the medium

Question 5

5. What is total internal reflection?

Accepted Answer

When a light ray travels from a denser medium to a rarer medium at an angle greater than the critical angle, it reflects back into the denser medium instead of refracting. This is called Total Internal Reflection (TIR). Example: Mirage in deserts.

Question 6

6. What is the difference between concave and convex mirrors?

Accepted Answer

Concave Mirror: A mirror with a reflecting surface curved inward, used in torches, headlights, and shaving mirrors.
Convex Mirror: A mirror with a reflecting surface curved outward, used in rear-view mirrors of vehicles.

Question 7

7. What are the uses of concave and convex lenses?

Accepted Answer

Convex Lens: Used in magnifying glasses, cameras, and human eyes to converge light.
Concave Lens: Used in spectacles for myopia (nearsightedness) and in laser devices to diverge light.

Question 8

8. What is the power of a lens?

Accepted Answer

The power (P) of a lens is the reciprocal of its focal length (f) in meters:
P=1/f (in diopters, D)
a) Convex lens has positive power.
b) Concave lens has negative power.

Question 9

9. Why does a pencil appear bent in water?

Accepted Answer

A pencil appears bent in water due to refraction—light changes speed and direction as it moves from water to air.

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