Entry Test MCQ :: Optical Instruments
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1. |
A lens which converges a beam of parallel rays to a point is called |
A. |
diverging (or concave) lens |
B. |
converging (or convex) lens |
C. |
plano concave lens |
D. |
plano convex lens |
Answer: Option B
Explanation:
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2. |
A point where the incident parallel rays of light converge or appear to diverge after passing through a lens is called |
A. |
center of curvature |
B. |
focus |
C. |
optical center |
D. |
aperture |
Answer: Option B
Explanation:
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3. |
The diameter of a lens is called |
A. |
focal length |
B. |
principal axis |
C. |
aperture |
D. |
radius of curvature |
Answer: Option C
Explanation:
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4. |
In going form a denser to rarer medium a ray of light is |
A. |
undeviated |
B. |
bent away form the normal |
C. |
bent towards the normal |
D. |
polarized |
Answer: Option B
Explanation:
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5. |
Unit of power of a lens is |
A. |
meter |
B. |
watt |
C. |
dioptre |
D. |
horsepower |
Answer: Option C
Explanation:
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6. |
Dioptre power of an concave lens of 10 cm focal length is |
A. |
10 dioptre |
B. |
10 dioptre |
C. |
1 / 10 dioptre |
D. |
1 / 10 dioptre |
Answer: Option B
Explanation:
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7. |
The power of a concave lens is |
A. |
real |
B. |
virtual |
C. |
positive |
D. |
negative |
Answer: Option D
Explanation:
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8. |
The minimum distance between an object and its real image in a convex lens is |
Answer: Option D
Explanation:
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9. |
If an object is placed away from 2f of a converging lens then the image will be |
A. |
real and erect |
B. |
virtual and erect |
C. |
real and inverted |
D. |
virtual |
Answer: Option C
Explanation:
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10. |
A convex lens gives a virtual image only when the objects lies |
A. |
between principal focus and center of curvature |
B. |
beyond 2 f |
C. |
at the principal focus |
D. |
between principal focus and optical center |
Answer: Option D
Explanation:
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