12
MCQ (Multiple Correct Answer)
Consider an extended object immersed in water contained in a plane trough. When seen from close to the edge of the trough the object looks distorted because
A
the apparent depth of the points close to the edge are nearer the surface of the water compared to the points away from the edge
B
the angle subtended by the image of the object at the eye is smaller than the actual angle subtended by the object in air
C
some of the points of the object far away from the edge may not be visible because of total internal reflection
D
water in a trough acts as a lens and magnifies the object
13
MCQ (Multiple Correct Answer)
A rectangular block of glass $A B C D$ has a refractive index 1.6. A pin is placed midway on the face $A B$ figure. When observed from the face $A D$, the pin shall
A
appear to be near $A$
B
appear to be near $D$
C
appear to be at the centre of $A D$
D
not be seen at all
14
MCQ (Multiple Correct Answer)
Between the primary and secondary rainbows, there is a dark band known as Alexandar's dark band. This is because
A
light scattered into this region interfere destructively
B
there is no light scattered into this region
C
light is absorbed in this region
D
angle made at the eye by the scattered rays with respect to the incident light of the sun lies between approximately $42^{\circ}$ and $50^{\circ}$
15
MCQ (Multiple Correct Answer)
A magnifying glass is used, as the object to be viewed can be brought closer to the eye than the normal near point. This results in
A
a larger angle to be subtended by the object at the eye and hence, viewed in greater detail
B
the formation of a virtual erect image
C
increase in the field of view
D
infinite magnification at the near point
16
MCQ (Multiple Correct Answer)
An astronomical refractive telescope has an objective of focal length 20 m and an eyepiece of focal length 2 cm .
A
The length of the telescope tube is 20.02 m
B
The magnification is 1000
C
The image formed is inverted
D
An objective of a larger aperture will increase the brightness and reduce chromatic aberration of the image