71
Rainbow is formed due to
A)
refraction and dispersion
B)
scattering and refraction
C)
diffraction and refraction
D)
refraction and reflection
Answer & Solution
Answer: Option
A
72
The red colour of the Sun at Sunset and Sunrise is due to
A)
Scattering of light
B)
Refraction of light
C)
Total internal reflection of light
D)
Dispersion of light
Answer & Solution
Answer: Option
A
73
What is the reason for the sun to appear long circular at sunrise and sunset?
A)
refraction
B)
reflection
C)
scattering
D)
diffusion
Answer & Solution
Answer: Option
A
74
This is not a use of a concave mirror
A)
in torches
B)
as shaving mirrors
C)
as rear view mirrors
D)
in headlights
Answer & Solution
Answer: Option
C
75
The primary colours used in colour television are
A)
Green, Yellow, Red
B)
Red, Yellow, Blue
C)
Red, Green, Blue
D)
Blue, Yellow, Green
Answer & Solution
Answer: Option
C
76
A microscope used in pathological laboratories forms
A)
magnified, virtual and erect image
B)
diminished, real and erect image
C)
magnified, virtual and inverted image
D)
diminished, virtual and erect image
Answer & Solution
Answer: Option
C
77
What is the velocity of light in vacuum?
A)
3 × 108 ms-1
B)
2 × 108 ms-1
C)
3 × 107 ms-1
D)
3 × 106 ms-1
Answer & Solution
Answer: Option
A
78
The focal length of a convex lens is . . . . . . . .
A)
positive
B)
negative
C)
zero
D)
infinite
Answer & Solution
Answer: Option
A
79
When light enters the denser medium through the rare medium, . . . . . . . .
A)
Its speed decreases first then increases
B)
its speed increases
C)
its speed decreases
D)
its speed remains the same
Answer & Solution
Answer: Option
C
80
The . . . . . . . . oval spot in the human eye is the area of best vision
A)
yellow
B)
white
C)
green
D)
blue
Answer & Solution
Answer: Option
A
