MCQ Collection
ECAT Physics MCQs
Practice ECAT Physics questions with answers and explanations.
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Correct Answer: B. Ratio of light speed in vacuum to light speed in a medium
Explanation:
Refractive index indicates how strongly a medium slows light.
It is dimensionless.
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Correct Answer: C. Angles of incidence and refraction to refractive indices
Explanation:
Snell's law is n1 sinθ1 = n2 sinθ2.
It predicts the bending of a ray at an interface.
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Correct Answer: D. Light travels from higher to lower refractive index at an angle greater than the critical angle
Explanation:
Beyond the critical angle, no transmitted ray propagates into the lower-index medium.
All light is reflected internally.
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Correct Answer: A. An image formed where light rays actually converge
Explanation:
A real image can be projected onto a screen.
It is usually inverted in simple lens and mirror systems.
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Correct Answer: B. 0.628 s
Explanation:
Period is T=2π/ω.
T=2π/10≈0.628 s.
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Correct Answer: B. An image formed where rays appear to originate
Explanation:
Virtual images arise from backward extensions of diverging rays.
They cannot be captured directly on a screen.
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Correct Answer: C. 20 m/s
Explanation:
Speed is distance divided by time.
8/0.4 = 20 m/s.
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Correct Answer: C. Virtual, upright, and same size
Explanation:
A plane mirror forms an image behind the mirror at equal distance.
Its lateral orientation is reversed.
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Correct Answer: D. 102 m
Explanation:
The sound travels to the wall and back, so distance to wall is vt/2.
340×0.6/2 = 102 m.
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Correct Answer: D. Point where parallel rays converge after refraction
Explanation:
A converging lens brings paraxial parallel rays to its principal focus.
The focal length is positive under the common sign convention.
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Correct Answer: A. 5 cm
Explanation:
In-phase displacements add constructively.
The resultant amplitude is 3+2 = 5 cm.
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Correct Answer: A. Makes them spread as if from a virtual focus
Explanation:
A diverging lens causes rays to separate.
Their backward extensions meet at a virtual focal point.
