The rays which are travelling parallel to the principal axis of a convex lens are ……………….
A) converge at focus
B) converge at centre of curvature
C) appear to diverge from the focus
D) none
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The refracted ray …………….. when a ray travelling parallel to the principal axis, strikes a convex surface and passes from rarer to denser medium
A) moves towards the principal axis
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The refracted ray ………………. when a ray travelling parallel to the principal axis, strikes a convex surface and passes
B) moves away from the principal axis
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What happens when parallel rays of light fall on a lens making some angle with the principal axis ?
D) The rays Converge at a point lying on the focal plane
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A virtual erect image is formed when an object is placed on the principal axis of a convex lens ………………….
D) between focal point and optic centre
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The Convex lens behaves as a converging lens if it is kept in a medium with refractive index less than the refractive index of the lens.
B) Both statements are false
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When a lens of focal length f is cut in to two equal halves perpendicular to principal axis, then the focal length of each part of the lens is ………………
Correct option is B) double
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A convex lens of focal length 20 cm is cut into two halves along principal axis then focal length of each part will be …………………
Correct option is A) 20 cm
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A convex lens of focal length 20 cm is cut into two halves perpendicular to the principal axis then focal length of each part will be ……………….
Correct option is C) 40 cm
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A point object O is placed on the principle axis of a convex lens of focal length 10 cm at 12 cm from the lens.
U = -12 f = -10 1/v - 1/u = 1/f 1/v + 1/12 = 1/10 1/v = 1/60 \(-\frac{1}{v^2} \)dv or \(\frac{1}{u^2} \)du du = \(\frac{v^2}{u^2} \)du \( \frac{v}{u} \)= same path △u1 = △u2 = 1mm △u1 = △v2 △v2 = vf - vi x2 = △v2 + 1mm x2...
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