(B) VERY SHORT ANSWER TYPE
1. Select the luminous object(s) from the following: Sun, Moon, Earth, Shooting star, Fire
Sun and Fire
2. What do you mean by reflection of light?
Reflection of light is the phenomenon in which light bounces back after striking a smooth surface such as a mirror.
3. Which surface of a plane mirror reflects most of the light incident on it?
The back silvered surface reflects most of the light.
4. A light ray is incident normally on a plane mirror.
(a) What is its angle of incidence?
(b) What is the direction of reflected ray?
(a) What is its angle of incidence?
(b) What is the direction of reflected ray?
(a) 0°
(b) The reflected ray retraces the same path as the incident ray.
(b) The reflected ray retraces the same path as the incident ray.
5. For a ray reflected on a plane mirror, find the ratio of sin i/sin r.
The ratio sin i / sin r = 1
6. Light from a torch is reflected by a white sheet of paper and a black polished mica sheet. Which of the two will produce a stronger reflected beam?
Black polished mica sheet will produce a stronger reflected beam.
7. A light ray strikes a mirror and retraces its path. What is the angle of incidence and angle of reflection?
Angle of incidence = 0°, Angle of reflection = 0°
(C) SHORT ANSWER TYPE
1. Explain the following terms: (a) plane mirror, (b) incident ray, (c) reflected ray, (d) angle of incidence, (e) angle of reflection.
(a) Plane mirror: A smooth, flat reflecting surface.
(b) Incident ray: The ray of light striking the mirror.
(c) Reflected ray: The ray bouncing off the mirror.
(d) Angle of incidence: The angle between the incident ray and the normal.
(e) Angle of reflection: The angle between the reflected ray and the normal.
(b) Incident ray: The ray of light striking the mirror.
(c) Reflected ray: The ray bouncing off the mirror.
(d) Angle of incidence: The angle between the incident ray and the normal.
(e) Angle of reflection: The angle between the reflected ray and the normal.
2. Differentiate between reflection of light from a plane mirror and that from a plane wall.
Plane mirror — Regular reflection producing clear images.
Plane wall — Irregular reflection producing no image.
Plane wall — Irregular reflection producing no image.
3. State the two laws of reflection of light.
1. The angle of incidence equals the angle of reflection.
2. The incident ray, reflected ray, and the normal all lie in the same plane.
2. The incident ray, reflected ray, and the normal all lie in the same plane.
4. (a) Write three characteristics of the image formed by a plane mirror.
(b) How is the position of image related to the position of the object?
(b) How is the position of image related to the position of the object?
(a) Image is virtual, erect, laterally inverted and of the same size as the object.
(b) The image is formed as far behind the mirror as the object is in front of it.
(b) The image is formed as far behind the mirror as the object is in front of it.
5. Differentiate between a real and a virtual image.
Real image — formed when light rays actually meet; can be obtained on a screen.
Virtual image — formed when rays appear to meet; cannot be obtained on a screen.
Virtual image — formed when rays appear to meet; cannot be obtained on a screen.
6. What is meant by lateral inversion of an image in a plane mirror? Explain with a ray diagram.
Lateral inversion is the interchange of the left and right sides of an image formed in a mirror.
For example, the left hand appears as the right hand in the mirror.
For example, the left hand appears as the right hand in the mirror.
7. The letters on the front of an ambulance are written laterally inverted . Give reason.
Because of lateral inversion, when seen in the rear-view mirror, the word ‘AMBULANCE’ appears correctly to the driver in front.
