Question Bank for 8th Class Physics Light Light Formative Objective Problems

1) Statement I: The plane containing the incident ray and the normal is called plane of incidence. Statement II: The plane containing the incident ray and the normal is called plane of reflection.

A) Both Statements are true, Statement-II is the correct explanation of Statement-I.

B) Both Statements are true. Statement-II is not correct explanation of Statement-I.

C) Statement-I is true, Statement-II is false.

D) Statement-I is false. Statement-II is true.

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2) When the rays of light, diverging from a point, after reflection or refraction, appear to diverge from another point, then the image so formed is called

A) Virtual image

B) Real image

C) Both (a) and (b)

D) Neither (a) nor (b)

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3) When the rays of light, diverging from a point, after reflection or refraction actually converge at some other point then that point is ___ image of the object

A) Virtual

B) Real

C) Both (a) and (b)

D) Neither (a) nor (b)

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4) You are standing in front of a plane mirror, which is approaching you with a speed of 10cm/sec. Then the speed of the image approaching you will be

A) 20 cm/s

B) 10 cm/s

C) 15 cm/s

D) 25 cm/s

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5) A lady dressed in a new sari stands in front of a plane mirror fixed on a vertical wall, height of the lady is 160 cm and that of her eyes from the ground is 150 cm, then The length of the mirror required to see her fall view in the mirror is

A) 160 cm

B) 100 cm

C) 80 cm

D) 320 cm

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6) In the above problem, find the position of lower edge of the mirror relative to the ground is

A) 160 cm

B) 75 cm

C) 100 cm

D) 200 cm

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7) A lady dressed in a new sari stands in front of a plane mirror fixed on a vertical wall, height of the lady is 160 cm and that of her eyes from the ground is 150 cm, then find the position of upper edge of the mirror relative to the ground is

A) 155 cm

B) 160 cm

C) 100 cm

D) 200 cm

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8) Statement I: A concave mirror has a real focus. Statement II: A convex mirror has a virtual focus.

A) Both Statements are true. Statement-II is the correct explanation of Statement-I.

B) Both Statements are true. Statement-II is not correct explanation of Statement-I.

C) Statement-I is true. Statement-II is false.

D) Statement-I is false. Statement-II is true.

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9) The image formed by a convex mirror of real object is larger than the object.

A) When u < 2f

B) When u > 2f

C) for all values ofu

D) for no value of u

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10) Statement I: The radius of curvature and focal length of convex mirror are 80 cm and 40 cm Statement II: The relation between radius of curvature and focal length is R = 2f.

A) Both Statements are true, Statement-II is the correct explanation of Statement-I.

B) Both Statements are true, Statement-II is not correct explanation of Statement-I.

C) Statement-I is true. Statement-II is false.

D) Statement-I is false. Statement-II is true.

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11) The property that which a light a ray passes obliquely from one medium into another it bends at interface is

A) Reflection

B) Refraction

C) Interference

D) Polarization

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12) Light starting from a medium of refractive index \[\mu \] undergoes refraction into a medium \[{{\mu }^{\text{l}}}\] If i and r stand for angles of incidence and refraction respectively, then

A) \[\frac{\sin i}{\sin r}=\frac{\mu }{{{\mu }^{\text{l}}}}\]

B) \[\frac{\sin i}{\sin r}=\frac{{{\mu }^{\text{l}}}}{\mu }\]

C) \[\frac{\cos i}{\cos r}=\frac{{{\mu }^{\text{l}}}}{\mu }\]

D) \[\frac{sini}{sinr}=\frac{1}{\mu {{\mu }^{\text{l}}}}\]

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13) When a light ray passes from one medium \[({{\mu }_{1}})\] to other medium \[({{\mu }_{2}})\]. Refraction does not take place in the following situation.

A) for normal incidence

B) \[{{\mu }_{1}}>{{\mu }_{2}}\]

C) \[{{\mu }_{1}}={{\mu }_{2}}\]

D) \[{{\mu }_{1}}<{{\mu }_{2}}\]

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14) Light of the wave length \[7200{{A}^{o}}\] in air has a wave length in glass is equal to (\[\mu =1.5\])

A) \[7200\overset{\text{o}}{\mathop{\text{A}}}\,\]

B) \[4800\overset{\text{o}}{\mathop{\text{A}}}\,\]

C) \[1080\overset{\text{o}}{\mathop{\text{A}}}\,\]

D) \[3600\overset{\text{o}}{\mathop{\text{A}}}\,\]

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15) A ray of light incident on a refracting surface. If the angle of incidence \[{{60}^{o}}\] and the angle of refraction is \[{{45}^{o}}\], then angle of deviation is

A) \[{{30}^{o}}\]

B) \[{{90}^{o}}\]

C) \[{{15}^{o}}\]

D) \[{{0}^{o}}\]

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16) The velocity of light in air is \[3\times {{10}^{8}}m{{s}^{-1}}\] and in glass is \[2\times 108m{{s}^{-1}}\].. The refractive index of glass w.r.t air is

A) 2/3

B) 3/2

C) 4/3

D) 9/4

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17) A fish is raising vertically to the surface of water in a lake uniformly at the rate of \[2m{{s}^{-1}}\] observes a bird diving vertically towards the water at a rate \[4m{{s}^{-1}}\] vertically above it. The refractive index of water is 4/3. The actual velocity of the bird is

A) 3/2

B) 2/3

C) 4/3

D) 3/4

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18) Which of the following diagrams correctly represents the ray of light passing through the optical centre?

A)

B)

C)

D)

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19) A ray of light is incident on a concave lens parallel to its principal axis. The path of the refracted ray is correctly depicted by

A)

B)

C)

D)

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20) An object AB is placed in front of a convex lens at its principal focus as shown in the Figure.

Which of the ray diagram given below correctly depicts the refraction through the lens L?

A)

B)

C)

D)

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21) Which of the following parts of the eye has enormous number of photo-sensitive cells?

A) Iris

B) Pupil

C) Retina

D) Cornea

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22) The focal length of the eye lens is adjusted by the

A) vitreous humour

B) aqueous humour

C) ciliary muscles

D) optic nerves

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23) In the human eye, the function of the optic nerves is to

A) adjust the focus of the eye lens

B) transmit electrical signals to the brain

C) control the number of rod and cone cells

D) convert light signals into electrical signals

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24) The primary function of the crystalline lens in the human eye is to

A) reduce the intensity of light

B) focus the incident light rays

C) adjust the size of the pupil

D) filter out the dust particles

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25) The given diagram is that of the human eye. In the given diagram, the parts labelled as I and II are respectively the

A) eye lens and the cornea

B) pupil and the eye lens

C) cornea and the pupil

D) pupil and the iris

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26) Four statements about the blind spot of the human eye: I It is devoid of photosensitive cells. II No image is formed at the blind spot. III It connects the optic nerves to the retina. IV Its malfunctioning makes a person blind. Which of the given statements is incorrect?

A) I

B) II

C) III

D) IV

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27) When we look at a distant object, the ciliary muscles__i__, making the eye lens __ii__. This iii the focal length of the eye lens so that the image of that object gets focused on the retina. The information in which alternative completes the given statements?

A) i-get released, ii-thicker, iii-decreases

B) i-contract, ii-thicker, iii-increases

C) i-get released, ii-thinner, iii-increses

D) i-contract, ii-thinner, iii-decreases

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28) Which of the following pairs of eye parts is responsible for controlling the amount of light entering into the eye?

A) Iris and pupil

B) Cornea and eye lens

C) Cilliary muscles and iris

D) Cilliary muscles and pupil

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29) Tina has a defect in her eyes. She is not able to contract her iris properly. As a result of the defect in her eyes, Tina will not be able to see

A) in dim light

B) near objects

C) in bright light

D) distant objects

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30) The range of vision of a normal human eye lies between

A) 25 m and infinity

B) 2.5 m and 5 km

C) 2.5 cm and 5 km

D) 25 cm and infinity

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31) Myopia is a defect of vision caused by

A) a decrease in the retinal distance from the lens

B) a decrease in the diameter of the eyeball

C) an increase in the thickness of the lens

D) an increase in the curvature of the lens

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32) Shyam views a certain object and finds that it is not properly visible to him. The image of the said object is formed by his eye lens 3 cm away from the pupil of his eye.Shyam can correct the defect in his vision by using

A) convex lens

B) bifocal lens

C) concave lens

D) cylindrical lens

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8th Class Physics Light Question Bank

Light Formative Objective Problems

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8th Class Physics Light Question Bank

done Light Formative Objective Problems

Light Formative Objective Problems