Optics Answers

Calculate the critical angle for light passing from rock salt into air given that the refractive index of rock salt is 1.54

37.4 degrees
40.5 degrees
53.2 degrees
67.3 degrees

The refractive index of diamond is given as 2.42. A ray of yellow light of wavelength 589 nm passes through a rectangular diamond block in 1.32×10−9 s. What is the thickness of the block?

10.5 cm
12.7 cm
16.4 cm
22.3 cm

What is the refractive index of glass material for which the speed of light in it is
1.92×108 m/s?

2.41
1.56
0.54
1.35

The speed of light _____________

has never been measured
is about the same as that of sound
is infinitely fast
is very large, but not infinitee

How far in front of a concave spherical mirror with a focal length f would you place a candle so that it appears to burn from both sides?

4 f
2 f
f
1/2 f

A concave mirror has a focal length of 20 cm. Where is the image located when the object is placed 60 cm from the mirror?

15 cm in front
30 cm in front
60 cm in front
15 cm at the back

What image is formed when an object is placed between the focal point and the centre of curvature of a concave mirror?

erect and virtual
inverted and virtual
erect and real
inverted and real

A certain concave mirror is found to form an image of the Sun at a distance of 8 m from the mirror. What is the radius of curvature of this mirror?

8 m
12 m
16 m
24 m

What is the the focal length of a convex mirror which produces an image 1/5 the size of an object located 17 cm from the mirror?
−2.4cm
3.2cm
−4.2cm
5.3cm

An object placed in front of a concave mirror of radius 20 cm produces an inverted image which is one-fifth the size of the object. How far is the object from the mirror?
30 cm
40 cm
50 cm
60 cm