NTSE SAT Physics Light Refraction and Lens MCQs

Question: The refractive index of air relative to glass is 2/3 and that of diamond relative to air is 12/5. The refractive index of glass relative to diamond is :

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: Monochromatic light is refracted from air into a medium of refractive index n. The ratio of wavelength of the incident and refracted waves is :

• a) 1 : 1
• b) 1 : n
• c) n : 1
• d) n2 : 1

Answer: n : 1

Question: Total internal reflection occurs when light travels from :

• a) A rare medium to a denser medium and the angle of incidence is less than the critical angle
• b) A denser medium to rarer medium
• c) A rarer medium to denser medium
• d) A rarer medium to denser medium & the angle of incidence is greater than the critical angle

Answer: A denser medium to rarer medium

Question: Two lenses of powers + 6.0 D and -4.0 D are put in contact with each other. The power of the combination is :

• a) + 2.0 D
• b) -2.0 D
• c) + 5.0 D
• d) - 5.0 D

Answer: + 2.0 D

Question: Arrange the optical medium in ascending order according to optically denser :

• a) Air < Glass < Water
• b) Air < Water < Glass
• c) Water < Air < Glass
• d) Glass < Water < Air

Answer: Air < Water < Glass

Question: Which of the following would be you prefer to read very small letters printed on a page of dictionary ?

• a) A convex lens of focal length 100 cm
• b) A concave lens of focal length 10 cm
• c) A concave lens of focal length 5 cm
• d) A convex lens of focal length 5 cm

Answer: A convex lens of focal length 100 cm

Question: A thin lens is made with a material having refractive index  µ = 1.5. Both the sides are convex. It is dipped in water (µ= 1.33), it will behave like :

• a) A convergent lens
• b) A divergent lens
• c) A rectangular slab
• d) A prism

Answer: A convergent lens

Question: Refractive index of a glass is maximum for :

• a) Violet
• b) Yellow
• c) Blue
• d) Red

Answer: Violet

Question: The middle color in sunlight spectrum is :

• a) Yellow
• b) Green
• c) Blue
• d) Orange

Answer: Yellow

Question: Refractive index of glass with respect to air is 1.5 and refractive index of water with respect to air is 4/3 . What will be the refractive index of glass with respect to water ?

• a) 1
• b) 1.5
• c) 1.125
• d) -10

Answer: 1.125

More Questions..............................

Question: A thin lens is made with a material having refractive index  µ = 1.5. Both the sides are convex. It is dipped in water (µ= 1.33), it will behave like :

• a) A convergent lines
• b) A divergent lens
• c) A rectangular slab
• d) A prism

Answer: A convergent lines

Question: In the refractive indices for water and diamond relative to air 1.33 and 2.4 respectively, then the refractive index of diamond relative to water is :

• a) 0.55
• b) 1.80
• c) 3.19
• d) None of these

Answer: 1.80

Question: Two thin lenses of focal length s 20 cm and 25 cm are placed in contact. The effective power of the combination is :

• a)

  

• b) 45 dioptre
• c) 6 dioptre
• d) 9 dioptre

Answer: 9 dioptre

Question: A rectangular glass plate is placed on a piece of paper which has a small dot of ink. When ink-dot is seen from the upper side of the plate, then it appears to be above 1 cm from the paper. If the refractive index glass is 1.5, then the thickness of the plate in cm will be:

• a) 1
• b) 1.5
• c) 2.5
• d) 3

Answer: 3

Question: A ray of light is incident on a glass slab normally. Calculate the percent change in the angle of refracted ray with respect to the normal. The refractive index of glass is 1.5 :

• a) 15%
• b) 1.5%
• c) 0.05 %
• d) 0%

Answer: 0%

Question: A fish looking up through the water sees the outside world contained in a circular horizon. If the refractive index of water is 4/3 and the fish is 12 cm below the surface, the radius of the circle is :

• a)

  

• b)

  

• c)

  

• d)

  

Answer:

Question: The depth of water in a tank is 4 meter. If the refractive index of water is 4/3 , by how much distance does the bottom of tank appear to be raised ?

• a) 1m
• b) 2m
• c) 3m
• d) 4m

Answer: 1m

Question: A small ink depot on a paper is viewed through a glass slab of thickness 10 cm, and refractive index 1.5. By what distance would the dot appear to the raised ?

• a) 3.33 cm
• b) 3.23 cm
• c) 3 cm
• d) .13 cm

Answer: 3.33 cm

Question: Velocity of light in a liquid is 1.5 × 108 m/s and in air, it is 3 × 108 m/s. If a ray of light passes from liquid into the air, calculate the value of critical angle.

• a) 400  
• b) 300
• c) 600
• d) 500

Answer: 300

Question: Two thin lenses are in contact and the focal length of the combination is 80 cm. If the focal length of one lens is 20 cm, then what would be the power of the other lens ?

• a) -3.25 D
• b) -3.5 D
• c) 3 D
• d) -3.75 D

Answer: -3.75 D

Question: Which of the following colors has the least wavelength ?

• a) Red
• b) Orange
• c) Violet
• d) Blue

Answer: Violet

Question: Two lenses of +5D and -5D are placed in chose contact. The focal length of the combination is.

• a) Zero
• b) ∞ 
• c) zero or ∞ 
• d) None of these

Answer: ∞ 

Question: A white light falls on a glass prism, the least deviated color is :

• a) Violet
• b) Orange
• c) Red
• d) Yellow

Answer: Red

Question: Which of the following color has the maximum wavelength ?

• a) Red
• b) Orange
• c) Violet
• d) Blue

Answer: Red

Question: Which of the following color has the maximum wavelength ?

• a) Red
• b) Orange
• c) Violet
• d) Blue

Answer: Red