8th Science - Light online quiz

 8th Science -  Light online quiz

 

1. Which of the following has curved reflecting surface?
a) plane mirrors
b) spherical mirrors
c) simple mirrors
d) None of the above

Answer: (b) spherical mirrors

2. The spherical mirror with a reflecting surface curved inward is called
a) convex mirror
b) concave mirror
c) curved mirror
d) None of the above

Answer: (b) concave mirror

3. The spherical mirror used as a rear view mirror in the vehicle is
a) concave mirror
b) convex mirror
c) plane mirror
d) None of the above

Answer: (b) convex mirror

4. The imaginary line passing through the centre of curvature and pole of a spherical mirror is called
a) centre of curvature
b) pole
c) principal axis
d) radius curvature

Answer: (c) principal axis

5. The distance from the pole to the focus is called
a) pole length
b) focal length
c) principal axis
d) None of the above

Answer: (b) focal length

6. If the image and object distance is same, then the object is placed at
a) infinity
b) at F
c) between f and P
d) at C

Answer: (d) at C

7. If the focal length of a spherical mirror is 10 cm, what is the value of its radius of curvature?
a) 10 cm
b) 5 cm
c) 20 cm
d) 15 cm

Answer: (c) 20 cm

1. The spherical mirror used in a beauty parlour as make-up mirror is
convex mirror plane mirror concave mirror simple mirror

Answer: concave mirror

2. Geometric centre of the spherical mirror is
focus pole centre of curvature radius of curvature

Answer: pole

3. Nature of the images formed by a convex mirror is
larger, virtual and erect smaller, virtual and erect same size, real and inverted smaller, real and inverted

Answer: smaller, virtual and erect

4. The mirror used by the ophthalmologist to examine the eye is
plane mirror concave mirror convex mirror simple mirror

Answer: concave mirror

5. If the angle of incidence is 45°, then the angle of reflection is
90° 45° 30° 60°

Answer: 45°

6. If an object is placed between two mirrors which are parallel to each other, the number of images formed is
finite infinite zero one

Answer: infinite

Match the following:

1. Convex mirror
2. Parabolic mirror
3. Snell’s law
4. Dispersion of light
5. Refractive index

• a) Rear-view mirror
• b) Radio telescopes
• c) Rainbow
• d) sin i/sin r = μ
• e) Kaleidoscope

1: a b c d e
2: a b c d e
3: a b c d e
4: a b c d e
5: a b c d e

Answer: 1-b, 2-a, 3-d, 4-e, 5-c