DELHI PUBLIC SCHOOL MEGACITY
SECOND REVIEW TEST
SUBJECT - PHYSICS
CLASS – 8
F.M. 10 Marks
Time: 30 min
1.The S.I. unit of work is
(a) second
(b) metre
(c) joule
(d) newton
2. When a body falls freely towards the earth, then its total energy
(a) Decreases
(b) Increases
(c) First increases and then decreases
(d) Remains constant
3. If the velocity of a body is doubled its kinetic energy
(a) gets doubled
(b) becomes half
(c) does not change
(d) becomes 4 times
4. 1 watt = …………..
(a) 9.8 Js
(b) 1 Js
(c) 9.8 J/s
(d) 1 J/s
5. Water stored in a dam possesses
(a) no energy
(b) potential energy
(c) kinetic energy
(d) electrical energy
6. A ray of light moving from an optically denser to a rarer medium
(a) bends away from the normal
(b) bends towards the normal
(c) remains undeviated
(d) none of the above
7. A ray of light passing through the centre of curvature of a spherical mirror, after reflection
(a) passes through the focus
(b) passes through the pole
(c) becomes parallel to the principal axis
(d) retraces its own path
8. If the radius of curvature of a concave mirror is 20 cm its focal length is
(a) 10 cm
(b) 20 cm
(c) 40 cm
(d) 80 cm
9. The image formed by a concave mirror is of the same size as the object, if the object is placed
(a) at the focus
(b) between the pole and focus
(c) between the focus and centre of curvature
(d) at the centre of curvature
10. A convex mirror is used
(a) as a shaving mirror
(b) as a head mirror by a dentist
(c) as a rear view mirror by a driver
(d) as a reflector in the torch.
Answer Key :
1
2
c
d
3
d
4
d
5
b
6
a
7
d
8
a
9
d
10
c