Reflection & Refraction — Homi Bhabha Class 9 Physics MCQs with Solutions
Free Homi Bhabha Class 9 Physics Reflection & Refraction MCQs with step-by-step solutions (9 questions). Part of Light & Optics. Practise online on Prepizo — no login needed.
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Questions with solutions
Q1 — Reflection & Refraction · medium · theory
According to the laws of reflection, the angle of incidence is:
A. less than the angle of reflection
B. greater than the angle of reflection
C. equal to the angle of reflection ✓ Correct
D. always 90°
Solution: The angle of incidence equals the angle of reflection, both measured from the normal.
Q2 — Reflection & Refraction · hard · numerical
A ray of light strikes a plane mirror making an angle of 30° with the mirror surface. The angle of reflection (measured from the normal) is:
A. 120°
B. 30°
C. 90°
D. 60° ✓ Correct
Solution: The angle of incidence from the normal $= 90° - 30° = 60°$, so the angle of reflection is also 60°.
Q3 — Reflection & Refraction · medium · theory
When light travels from air into a denser medium such as glass, it bends:
A. away from the normal
B. along the surface
C. back into air
D. towards the normal ✓ Correct
Solution: On entering a denser medium light slows down and bends towards the normal (refraction).
Q4 — Reflection & Refraction · medium · theory
A pencil placed in a glass of water appears bent at the water surface because of:
A. dispersion of light
B. absorption of light
C. refraction of light ✓ Correct
D. reflection of light
Solution: Light from the submerged part bends as it leaves the water, making the pencil appear bent.
Q5 — Reflection & Refraction · hard · theory
The speed of light is greatest in:
A. diamond
B. vacuum ✓ Correct
C. glass
D. water
Solution: Light travels fastest in vacuum; denser media (water, glass, diamond) slow it down.
Q6 — Reflection & Refraction · easy · theory
The angle of incidence of a ray of light striking a surface is measured between the incident ray and which line?
A. The horizontal ground
B. The reflecting surface
C. The normal drawn at the point of incidence ✓ Correct
D. The reflected ray
Solution: By definition, the angle of incidence is the angle between the incident ray and the normal (the perpendicular) drawn at the point where the ray meets the surface, not the surface itself.
Q7 — Reflection & Refraction · medium · numerical
A ray of light strikes a plane mirror making an angle of 30 degrees with the surface of the mirror. What is the angle of reflection, measured from the normal?
A. 90 degrees
B. 30 degrees
C. 60 degrees ✓ Correct
D. 120 degrees
Solution: The normal is perpendicular to the mirror, so the angle of incidence measured from the normal is 90 - 30 = 60 degrees. By the law of reflection, the angle of reflection equals the angle of incidence, which is 60 degrees.
Q8 — Reflection & Refraction · medium · theory
A ray of light passes from air into water. Because water is optically denser than air, the refracted ray:
A. Is totally reflected back into the air
B. Bends away from the normal
C. Bends toward the normal ✓ Correct
D. Travels straight without bending
Solution: Light slows down when it enters a denser medium such as water, so the ray bends toward the normal. It would bend away from the normal only when moving into a rarer medium.
Q9 — Reflection & Refraction · hard · numerical
The refractive index of a glass block is 1.5 and the speed of light in vacuum is 3 x 10 to the power 8 m/s. What is the speed of light inside the glass?
A. 2.5 x 10 to the power 8 m/s
B. 2 x 10 to the power 8 m/s ✓ Correct
C. 1.5 x 10 to the power 8 m/s
D. 4.5 x 10 to the power 8 m/s
Solution: Refractive index n = c/v, so v = c/n = (3 x 10 to the power 8) / 1.5 = 2 x 10 to the power 8 m/s. Choosing 4.5 x 10 to the power 8 wrongly multiplies instead of divides.