Class 10 Refraction of Light at Plane Surfaces Mock Test (ICSE)

Topics in Refraction of Light at Plane Surfaces

• Laws of refraction and refractive index
• Refraction through a glass block and lateral shift
• Real and apparent depth
• Refraction through a prism
• Critical angle and total internal reflection

Refraction of Light at Plane Surfaces practice questions with answers

1. Q1Multiple choice·1 mark
   When a ray of light travels from a denser medium to a rarer medium at an angle of incidence greater than the critical angle, it undergoes:

   1. (a)zero deviation without any change in speed.
   2. (b)total internal reflection obeying laws of reflection.
   3. (c)complete absorption by the boundary.
   4. (d)normal refraction obeying Snell's law.
   Show answer and step marks

   1. Correct option: (b) total internal reflection obeying laws of reflection.+1

   Answer: (b)
2. Q2Multiple choice·1 mark
   The critical angle for light passing from glass to air is $45^\circ$. The refractive index of glass with respect to air is:

   1. (a)$1.500$
   2. (b)$1.414$
   3. (c)$1.732$
   4. (d)$0.707$
   Show answer and step marks

   1. Correct option: (b) $1.414$ ($\mu = \frac{1}{\sin C} = \frac{1}{\sin 45^\circ} = \sqrt{2} \approx 1.414$)+1

   Answer: (b)
3. Q3Multiple choice·1 mark
   A ray of light is incident normally on one face of a rectangular glass slab. The angle of refraction at this face is:

   1. (a)$45^\circ$
   2. (b)$90^\circ$
   3. (c)$42^\circ$
   4. (d)$0^\circ$
   Show answer and step marks

   1. Correct option: (d) $0^\circ$+1

   Answer: (d)
4. Q4Multiple choice·1 mark
   A ray of light passes through an equilateral glass prism. As the angle of incidence increases from a small value, the angle of deviation:

   1. (a)first increases, reaches a maximum value, and then decreases.
   2. (b)continuously decreases.
   3. (c)continuously increases.
   4. (d)first decreases, reaches a minimum value, and then increases.
   Show answer and step marks

   1. Correct option: (d) first decreases, reaches a minimum value, and then increases.+1

   Answer: (d)
5. Q5Long answer·4 marks
   (a) State two factors on which the angle of deviation produced by a prism depends. (b) A ray of light is incident at an angle of $48^\circ$ on one face of a prism of refracting angle $60^\circ$. If the angle of emergence is $52^\circ$, calculate the angle of deviation.
   Show answer and step marks

   1. (a) First factor, any one of: the angle of incidence; the refractive index of the material of the prism; the refracting angle of the prism; the colour (wavelength) of the light used; or any other valid factor.+1
   2. (a) Second factor, a different one from the same list.+1
   3. (b) Formula and substitution: $\delta = i_1 + i_2 - A = 48^\circ + 52^\circ - 60^\circ$+1
   4. (b) Final answer with unit: $\delta = 40^\circ$+1

   Answer: (a) Any two of: angle of incidence, refractive index of the prism material, refracting angle of the prism, colour (wavelength) of light. (b) $\delta = 40^\circ$

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