(A) 0.4 (B) 0.8 (C) 1.3 (D) 1.6 Continue reading An extended object is placed at point O …
A glass tumbler having inner depth of 17.5 cm is kept on a table. A student starts pouring water $(\mu = 4/3 )$ into it while looking at the surface of water from the above. When he feels that the tumbler is half filled, he stops pouring water. Up to what height, the tumbler is actually filled?
(A) 11.7 cm
(B) 8.75 cm
(C) 7.5 cm
(D) 10 cm
Solution
$\mu = \frac {Real\, Depth}{Apparent\, Depth} = \frac {17.5-y}{y}$
$\therefore \frac {4}{3} = \frac {17.5-y}{y} $
$\therefore y = 7.5 cm$
Real Depth = 17.5 – y = 10 cm
Answer: (D)
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Question (one option correct type):
A beam of light passes through a hollow glass prism. Then,
A) the beam of light undergoes lesser but some dispersion compared to solid glass prism
B) the beam of light is totally internally reflected and does not come out through the opposite face
C) the beam of light does not undergo dispersion at all and comes out parallel to the incident ray
D) the beam of light undergoes angular deviation
Continue reading Hollow Prism Q & A
Diameter of a plano – convex lens is 6 cm and thickness at the centre is 3 mm. If speed of light in material of lens is 
m/s, the focal length of the lens is:
(1) 15 cm (2) 20 cm (3) 30 cm (4) 10 cm
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