CLASS: X NCERT (CBSE)

PHYSICS

Light-Reflection and Refraction

Multiple Choice Questions

Light-Reflection

Question 1: Light is a form of energy produced by a ______ .

1. luminous object

2. transparent object

3. non-luminous object

4. opaque object

Answer: 1

Question 2: An example for non-luminous object is ___________.

1. a candle

2. the sun

3. an electric bulb

4. the moon

Answer: 4

Question 3: 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

Answer: 2

Question 4: When light is incident on a polished surface ___________ reflection takes place.

1. regular

2. irregular

3. diffused

4. normal

Answer: 1

Question 5: An object becomes invisible when it undergoes ______ reflection.

1. regular

2. irregular

3. diffused

4. normal

Answer: 1

Question 6: According to the laws of reflection,

1. i = r

2. i > r

3. r > i

4.

Answer: 1

Question 7: 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

Answer: 2

Question 8: 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

Answer: 1

Question 9: The focus of a concave mirror is ________.

1. real

2. virtual

3. undefined

4. at the pole

Answer: 2

Question 10: A converging mirror is known as ________.

1. convex mirror

2. plane mirror

3. concave mirror

4. cylindrical mirror

Answer: 3

Question 11: 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

Answer: 3

Question 12: Radius of curvature of a concave mirror is always _____ to the mirror.

1. parallel

2. perpendicular

3. inclined at 60o

4. inclined at 45o

Answer: 2

Question 13: 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

Answer: 1

Question 14: 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

Answer: 1

Question 15: Dentists use a _____________ to focus light on the tooth of a patient.

1. concave mirror

2. convex mirror

3. plane mirror

4. cylindrical mirror

Answer: 1

Question 16: 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

Answer: 1

Question 17: 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

Answer: 3

Question 18: What is the value of q in the following diagram?

1. 30o

2. 45o

3. 90o

4. 60o

Answer: 4

Question 19: 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

Answer: 4

Question 20: Name the type of image that can be obtained on a screen.

1. Virtual

2. Real

3. Diverging

4. Converging

Answer: 2

Question 21: 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

Answer: 4

Question 22: 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

Answer: 4

Question 23: Which of the following is used to make a periscope?

1. Concave mirror

2. Convex mirror

3. Plane mirror

4. Lens

Answer: 3

Question 24: Which mirror has a wider field of view?

1. Convex mirror

2. Concave mirror

3. Plane mirror

4. Cylindrical mirror

Answer: 1

Question 25: 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

Answer: 2

Question 26: 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

Answer: 3

Question 27: A ray of light passing through the _______ retraces its path.

1. focus

2. centre of curvature

3. pole

4. vertex

Answer: 2

Question 28: 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

Answer: 1

Question 29: Butter paper is an example for _______ object.

1. a transparent

2. a translucent

3. an opaque

4. a luminous

Answer: 2

Question 30: 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

Answer: 4

Question 31: 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

Answer: 4

Light-Refraction

Question 1: The bending of a beam of light when it passes obliquely from one medium to another is known as _______.

1. reflection

2. refraction

3. dispersion

4. deviation

Answer: 2

Question 2: The part of the lens through which the ray of light passes without suffering deviation is called ________.

1. optical centre

2. focus

3. centre of curvature

4. pole

Answer: 1

Question 3: Convex lens always gives a real image if the object is situated beyond _______.

1. optical centre

2. centre of curvature

3. focus

4. radius of curvature

Answer: 3

Question 4: Parallel rays of light entering a convex lens always converge at _______.

1. centre of curvature

2. the principal focus

3. optical centre

4. the focal plane

Answer: 2

Question 5: Where should an object be placed so that a real and inverted image of the same size is obtained, using a convex lens?

1. Between O and F

2. At F

3. At 2 F

4. At infinity

Answer: 3

Question 6: SI unit of the power of a lens is ___________.

1. dioptre

2. cm

3. metre

4. watt

Answer: 1

Question 7: 1 D is the power of the lens of focal length of ______ cm.

1. 100

2. 10

3. 1/100

4. 1/10

Answer: 1

Question 8: In a simple microscope lens used is __________.

1. biconvex

2. biconcave

3. plano convex

4. cylindrical

Answer: 1

Question 9: Reciprocal of focal length in metres is known as the ______ of a lens.

1. focus

2. power

3. power of accommodation

4. far point

Answer: 2

Question 10: A convex lens is called _________.

1. converging lens

2. diverging lens

3. both converging and diverging lens

4. refracting lens

Answer: 1

Question 11: A positive magnification greater than unity indicates _____________________.

1. real image

2. virtual image

3. neither real not virtual image

4. distorted image

Answer: 2

Question 12: The power of a convex lens of focal length 50 cm is ______.

1. + 2D

2. – 2D

3. 50 D

4. – 5D

Answer: 1

Question 13: The focal length of a lens whose power is -1.5 D is _______.

1. -66.66 cm

2. + 1.5 m

3. + 66.66 cm

4. -1.5 m

Answer: 1

Question 14: Real images formed by single convex lenses are always ________________.

1. on the same side of the lens as the object

2. inverted

3. erect

4. smaller than the object

Answer: 2

Question 15: An object is placed 12 cm from a convex lens whose focal length is 10 cm. The image must be.

1. virtual and enlarged

2. virtual and reduced in size

3. real and reduced in size

4. real and enlarged

Answer: 4

Question 16: When a person uses a convex lens as a simple magnifying glass, the object must be placed at a distance.

1. less than one focal length

2. more than one focal length

3. less than twice the focal length

4. more than twice the focal length

Answer: 1

Question 17: The image produced by a concave lens is ________.

1. always virtual and enlarged

2. always virtual and reduced in size

3. always real

4. sometimes real, sometimes virtual

Answer: 2

Question 18: A virtual image is formed by _______.

1. a slide projector in a cinema hall

2. the ordinary camera

3. a simple microscope

4. telescope

Answer: 3

Question 19: An object is placed 25 cm from a convex lens whose focal length is 10 cm. The image distance is ________ cm.

1. 50 cm

2. 16.66 cm

3. 6.66 cm

4. 10 cm

Answer: 2

Question 20: The least distance of distinct vision is ______.

1. 25 cm

2. 25 m

3. 0.25 cm

4. 2.5 m

Answer: 1

Question 21: A convex lens has a focal length of 20 cm. Its power in dioptres is ___________.

1. 2

2. 5

3. 0.5

4. 0.2

Answer: 2

Question 22: An object is placed before a concave lens. The image formed _____________-.

1. is always erect

2. may be erect or inverted

3. is always inverted

4. is always real

Answer: 1

Question 23: A ray of light travels from a medium of refractive index n1 to a medium of refractive index n2. If angle of incidence is i and the angle of refraction is r.

Then is equal to

1. n1

2. n2

3. n21

4. n12

Answer: 3

Question 24: Two thin lenses of power +5 D and -2 D are placed in contact with each other. Focal length of the combination is

1. +3 m

2. -3 m

3. 0.33 m

4. -0.33 m

Answer: 3

Question 25: The lens formula in cartesian frame is ______________.

1.

2.

3.

4.

Answer: 3