 LIGHT

## Question 1

Question:   Light is a form of energy produced by a ______.

 1 luminous object 2 transparent object 3 non-luminous object 4 opaque object

## Question 2

Question:   An example for non-luminous object is ___________.

 1 a candle 2 the sun 3 an electric bulb 4 the moon

## Question 3

Question:   The phenomenon by which the incident light falling on a surface is sent back into the same medium is known as ________.

 1 polarization 2 reflection 3 refraction 4 absorption

## Question 4

Question:   When light is incident on a polished surface ___________ reflection takes place.

 1 regular 2 irregular 3 diffused 4 normal

## Question 5

Question:   An object becomes invisible when it undergoes ______ reflection.

 1 regular 2 irregular 3 diffused 4 normal

## Question 6

Question:   According to the laws of reflection,

 1 i = r 2 i > r 3 r > i 4 ## Question 7

Question:   The image formed by a plane mirror is always _______.

 1 real and erect 2 virtual and erect 3 real and inverted 4 virtual and inverted

## Question 8

Question:   The centre of the sphere of which the spherical mirror forms a part is called ____________.

 1 centre of curvature 2 focus 3 pole 4 vertex

## Question 9

Question:   The focus of a concave mirror is ________.

 1 real 2 virtual 3 undefined 4 at the pole

## Question 10

Question:   A converging mirror is known as ________.

 1 convex mirror 2 plane mirror 3 concave mirror 4 cylindrical mirror

## Question 11

Question:   The relation between the focal length and radius of curvature of a mirror is _______.

 1 2 R + 2 = f 3 f = R/2 4 f = 2 R

## Question 12

Question:   Radius of curvature of a concave mirror is always _____ to the mirror.

 1 parallel 2 perpendicular 3 inclined at 60o 4 inclined at 45o

## Question 13

Question:   An image formed by a convex mirror is always ________.

 1 virtual, erect and diminished 2 virtual, real and magnified 3 real, inverted and diminished 4 real, erect and magnified

## Question 14

Question:   If the image formed by a concave mirror is virtual, erect and magnified, then the object is placed __________.

 1 between the pole of the mirror and the focus 2 beyond the centre of curvature 3 at the centre of curvature 4 at the focus

## Question 15

Question:   Dentists use a _____________ to focus light on the tooth of a patient.

 1 concave mirror 2 convex mirror 3 plane mirror 4 cylindrical mirror

## Question 16

Question:   An object is placed 1.5 m from a plane mirror. How far is the image from the person?

 1 3 m 2 1.5 m 3 2 m 4 1 m

## Question 17

Question:   An object placed 2m from a plane mirror is shifted by 0.5 m away from the mirror. What is the distance between the object and its image?

 1 2 m 2 1.5 m 3 5 m 4 3 m

## Question 18

Question:   What is the value of q in the following diagram? 1 30o 2 45o 3 90o 4 60o

## Question 19

Question:   What is the angle between the incident and reflected rays when a ray of light is incident normally on a plane mirror?

 1 90o 2 45o 3 180o 4 0

## Question 20

Question:   Name the type of image that can be obtained on a screen.

 1 Virtual 2 Real 3 Diverging 4 Converging

## Question 21

Question:   A ray of light is incident on a plane mirror and the angle of incidence is 25o. What is the angle of reflection?

 1 0 2 50o 3 90o 4 25o

## Question 22

Question:   A ray of light is incident on a plane mirror and the angle of reflection is 50o. Calculate the angle between the incident ray and the reflected ray.

 1 50o 2 25o 3 90o 4 100o

## Question 23

Question:   Which of the following is used to make a periscope?

 1 Concave mirror 2 Convex mirror 3 Plane mirror 4 Lens

## Question 24

Question:   Which mirror has a wider field of view?

 1 Convex mirror 2 Concave mirror 3 Plane mirror 4 Cylindrical mirror

## Question 25

Question:   The focal length of a concave mirror is 15 cm. What is its radius of curvature?

 1 15 cm 2 30 cm 3 7.5 cm 4 45 cm

## Question 26

Question:   The focal length of a mirror is 15 cm. Identify the type of mirror.

 1 Concave mirror 2 Plane mirror 3 Convex mirror 4 Cylindrical mirror

## Question 27

Question:   A ray of light passing through the _______ retraces its path.

 1 focus 2 centre of curvature 3 pole 4 vertex

## Question 28

Question:   When an object is placed at the focus of a concave mirror, the image will be formed at ________.

 1 infinity 2 focus 3 centre of curvature 4 pole

## Question 29

Question:   Butter paper is an example for _______ object.

 1 a transparent 2 a translucent 3 an opaque 4 a luminous

## Question 30

Question:   An object of size 2.0 cm is placed perpendicular to the principal axis of a concave mirror. The distance of the object from the mirror equals to the radius of curvature. The size of the image will be ______________.

 1 0.5 cm 2 1.5 cm 3 1.0 cm 4 2.0 cm

## Question 31

Question:   If an incident ray passes through the centre of curvature of a spherical mirror, the reflected ray will __________________.

 1 pass through the focus 2 pass through the centre of curvature 3 pass through the pole 4 retrace its path

Light -Reflection and Refraction
(Q.15) Negative value of focal length of a spherical mirror indicates that it is
(a) Concave mirror(b) Convex mirror(c) Plane mirror(d) Convex mirror of small focal length

(Q.16) Light is a form of ___________ radiation
(a) Electrical (b) Mechanical (c) Longitudinal (d) Electomagnetic

(Q.17) A ________ image can be obtained on a screen.
(a) Real (b) Virtual (c) Erect (d) Inverted

(Q.18) Refraction of light can take place at the boundary of
(a) Transparent media (b) Opaque media (c) Any medium (d) Rarer medium

(Q.19) According to the laws of reflection
(a) Angle i = Angle r (b) Sine i = sine r (c) Sine i / Sine r = constant (d) tan i = tan r

(Q.20) An object placed at F of a concave mirror will produce an image
(a) At focus (b) Diminished (c) Real and Inverted (d) Virtual

(Q.21) An object placed at infinity of a concave mirror will produce an image
(a) Behind the mirror (b) Diminished (c) Virtual and erect (d) Enlarge

(Q.22) An object placed at F of a concave lens will produce an image
(a) On opposite side of the object (b) Enlarge (c) Virtual and erect(d) Real and inverted

(Q.23) An object placed at 2F of a convex lens will produce an image
(a) At 2F (b) Enlarge (c) Real and Inverted (d) Virtual
(Q.24) An object placed between F and 2F of a convex lens will produce an image

(a) Virtual (b) Diminished (c) Real and Inverted (d) Erect

(Q.25) According to the laws of refraction (Snell’s law)
(a) Angle i = Angle r (b) Sine i = sine r (c) Sine i / Sine r = constant(d) an i= tan r
(Q.26) Absolute Refractive index of a substance is

(a) Speed of light in vacuum / Speed of light in the medium
(b) Speed of light in water / Speed of light in the medium
(c) Speed of light in the medium / Speed of light in air
(d) Speed of light in medium/speed of light in water

(Q.27) According to Cartesian Sign Convention
(a) Object distance is always negative (b) Object distance is always positive
(c) Image distance is always negative (d) Image distance is always positive

(Q.28) Magnification produced by a concave mirror is
(a) Negative for a real image and Positive for a virtual image
(b) Only positive (c) It produces no magnification (d) Only negative

(Q.29) A ray of light propagates from an optically denser medium to an optically rarer medium.
(a) It will bend towards the normal after refraction.
(b) It will bend away from the normal after refraction.
(c) It will continue to go on the same path after refraction.
(d) It will refract making an angle of refraction equal to the angle of incidence.

(Q.30) Radius of curvature of a spherical mirror (or lens) is
(a) Half of its focal length (b) Double of its focal length
(c) Equal to its focal length (d) There is no relation

Q.31) The distance between a spherical lens and the image is – 15 cm. The lens is
(a) Concave lens(b) Convex lens(c) Either of the two irrespective of the object distance(d) Either Concave lens or Convex lens with object between O and F.

(Q.32) Power of a lens is
(a) Equal to its focal length (b) Reciprocal of the focal length (in meters)
(c) Square of its focal length (d) Reciprocal of its radius of curvature

(Q.33) Lens formula is expressed as
(a) 1/v - 1/u = 1/f (b) 1/v + 1/u = 1/f (c) 1/u - 1/v = 1/f (d) u + v = f

(Q.34) The colour of an object is determined by
(a) The colour of light reflected by it. (b) The colour of light absorbed by it.
(c) The colour of light incident on it only. (d) The colour of light transmitted by it.

(Q.35) The three primary colours are
(a) Red, Blue and Green (b) Red, Yellow and Blue (c) Red, White and Blue (d) Violet, Green and Red
(Q.36) Convex lenses are also called

(a) Converging lenses (b) Diverging lenses (c) Circular lenses (d) Plane lenses
Q.38) In which case the image formed by a concave mirror is of the same size as the object?
(a) When object is placed at infinity(b) When object lies at C(c) When object lies at F
(d) When object lies between C and F 