SSC CGL MCQ Practice 2026

Physics - Light Questions for SSC CGL (with Answers)

15 Physics - Light MCQs from the General Awareness section, with answers and short explanations.

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Q1. Which mirror is used as a rear-view mirror in vehicles?

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Answer: D. Convex mirror

Convex mirrors give an erect, diminished image with a wide field of view.

Physics - Light · easy · Beginner Practice Set 4

Q2. The focal length of a spherical mirror of radius of curvature 20 cm is:

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Answer: B. 10 cm

f = 20/2 = 10 cm.

Physics - Light · easy · Beginner Practice Set 7

Q3. The speed of light in vacuum is approximately:

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Answer: A. 3 × 10^8 m/s

Light travels at about 3 × 10^8 m/s in vacuum.

Physics - Light · easy · Beginner Practice Set 7

Q4. The part of the human eye on which the image is formed is the:

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Answer: C. Retina

The eye lens forms a real, inverted image on the retina.

Physics - Light · easy · Beginner Practice Set 8

Q5. The splitting of white light into its seven colours by a prism is called:

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Answer: A. Dispersion

Dispersion is the splitting of white light into its component colours.

Physics - Light · easy · Beginner Practice Set 10

Q6. The sparkling of a diamond is mainly due to:

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Answer: B. Total internal reflection

Diamond's high refractive index gives a small critical angle, causing repeated total internal reflection.

Physics - Light · medium · Intermediate Practice Set 2

Q7. Dentists and shaving mirrors commonly use a:

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Answer: A. Concave mirror

A concave mirror gives a magnified, erect image when the object is within its focus.

Physics - Light · medium · Intermediate Practice Set 3

Q8. Hypermetropia (long-sightedness) is corrected using a:

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Answer: C. Convex lens

A convex (converging) lens brings the image of near objects forward onto the retina.

Physics - Light · medium · Intermediate Practice Set 3

Q9. The sky appears blue because of:

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Answer: A. Scattering of light

Air molecules scatter blue light much more than red, so the sky looks blue.

Physics - Light · medium · Intermediate Practice Set 4

Q10. The power of a convex lens of focal length 50 cm is:

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Answer: C. +2 D

P = 1/0.5 m = +2 D (positive for a convex lens).

Physics - Light · medium · Intermediate Practice Set 6

Q11. Myopia (short-sightedness) is corrected using a:

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Answer: B. Concave lens

A concave (diverging) lens moves the image back onto the retina.

Physics - Light · medium · Intermediate Practice Set 7

Q12. The ability of the eye lens to adjust its focal length is called:

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Answer: A. Power of accommodation

Accommodation lets the eye focus on both near and distant objects.

Physics - Light · hard · Advanced Practice Set 1

Q13. The least distance of distinct vision for a normal young adult eye is about:

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Answer: D. 25 cm

The near point of a normal eye is about 25 cm.

Physics - Light · hard · Advanced Practice Set 4

Q14. An object is placed 30 cm from a convex lens of focal length 15 cm. The image distance is:

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Answer: B. 30 cm

1/v = 1/15 − 1/30 = 1/30, so v = +30 cm (object at 2F gives image at 2F).

Physics - Light · hard · Advanced Practice Set 4

Q15. The refractive index of glass is 1.5. The speed of light in glass is:

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Answer: A. 2 × 10^8 m/s

v = c/n = (3 × 10^8)/1.5 = 2 × 10^8 m/s.

Physics - Light · hard · Advanced Practice Set 7

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