PRACTICE PAPER 1

PHYSICS
1. If the real image of a candle flame formed by a lens is three times the size of the
flame and the distance between lens and image is 80 cm, at what distance
should the candle be placed from the lens?
a) -80cm b) -40 cm c) -40/3 cm d) -80/3 cm
2. While looking at the above diagram, Nalini concluded the following
i. The image of the object will be a virtual one.
ii. The reflected ray will travel along the same path as the incident ray but in opposite
direction.
iii. The image of the object will be inverted.
iv. This is a concave mirror and hence the focal length will be negative.
Which one of the above statements are correct?
a) i and ii b) i and iii c) ii, iii and iv d) i, ii, iii and iv
3. Which of the following can make a parallel beam of light when light from a point
source is incident on it?
a) Concave mirror as well as convex lens.
b) Convex mirror as well as concave lens.
c) Two plane mirrors placed at 90° to each other’s.
d) Concave mirror as well as concave lens.
4. Consider these indices of refraction: glass: 1.52; air: 1.0003; water: 1.333. Based
on the refractive indices of three materials, arrange the speed of light through
them in decreasing order.
a) The speed of light in water > the speed of light in air > the speed of light in glass.
b) The speed of light in glass > the speed of light in water > the speed of light in air.
c) The speed of light in air > the speed of light in water > the speed of light in glass.
d) The speed of light in glass > the speed of light in air > the speed of light in water.
5. If the power of a lens is - 2.0 D, then it means that the lens is a
a) Concave lens of focal length -50 m b) Convex lens of focal length +50 cm
c) Concave lens of focal length -25 cm d) Convex lens of focal length -25 m
6. Rays from Sun converge at a point 10 cm in front of a concave mirror. Where an
object should be placed so that size of its image is equal to the size of the object?
a) 20 cm in front of the mirror
b) 10 cm in front of the mirror
c) Between 10 cm and 20 cm in front of the mirror
d) More than 20 cm in front of the mirror
7. The refractive index of flint glass is 1.65 and that for alcohol is 1.36 with respect
to air. What is the refractive index of the flint glass with respect to alcohol?
a) 0.82 b) 1.21 c) 1.11 d) 1.01
8. One of the following does not apply to a concave mirror. This is:
a) Focal length is negative.
b) Image distance can be positive or negative.
c) Image distance is always positive.
d) Height of image can be positive or negative.
9. Where should an object be placed in front of a convex lens to get a real image of
the size of the object?
a) At the principal focus of the lens.
b) At twice the focal length.
c) At infinity.
d) Between the optical centre of the lens and its principal focus.
Questions 10 to 12 are Assertion- Reason type questions,
In each of the following, a statement of assertion is given followed by a
corresponding statement of reason just below it. Of the statements, mark the
correct answer as
a) Both assertion and reason are correct and reason is the correct explanation of assertion.
b) Both assertion and reason are correct but reason is not the correct explanation of
assertion.
c) Assertion is correct but reason is incorrect.
d) Assertion is incorrect but reason is correct.
10. Assertion: Light travels faster in glass than in air.
Reason: Glass is denser than air.
11. Assertion: The centre of curvature is not a part of the mirror. It lies outside its
reflecting surface.
Reason: The reflecting surface of a spherical mirror forms a part of a sphere. This
sphere has a centre.
12. Assertion: The emergent ray is parallel to the direction of the incident ray.
Reason: The extent of bending of the ray of light at the opposite parallel faces of the
rectangular glass sab is equal and opposite.
SECTION B
13. Draw ray diagrams to show the principal focus of (i) a concave mirror, and (ii) a convex
mirror.
14. Find the focal length of the mirror having radius of curvature 24 cm.
15. Find the focal length of the lens having power -2 D. Also state the nature of the lens.
16. Write the uses of Convex and Concave mirror.
SECTION C
17. Make labelled ray diagrams to illustrate the formation of:
(a) A real image by a converging mirror.
(b) A virtual image by a converging mirror.
Mark clearly the pole, focus, centre of curvature and position of object in each case.
18. An image 2/3rd the size of object is formed by a convex lens at a distance of 12cm
from Find the focal length of the lens.
19. The above image shows a thin lens of focal length 5m.
 (i) What is the kind of lens shown in the above figure?
(ii) If a real inverted image is to be formed by this lens at a distance of 7m from the
pole, then show with calculation where should the object be placed?

(iii) Draw a neatly labelled diagram of the image formation mentioned in (ii)
20. Define the following terms in the context of spherical mirrors:
(i) Pole. (ii) Centre of curvature. (iii) Radius of curvature.
SECTION D
21. A student wants to project the image of a candle flame on the walls of school laboratory
by using a lens:
(a) Which type of lens should he use and why?
(b) At what distance in terms of focal length ‘f’ of the lens should he place the candle
flame so as to get.
(i) A magnified (ii) A diminished image respectively on the wall?
(iii) Draw ray diagram to show the formation of the image each case.

22. Analyse the following observation table showing variation of image distance (v) with
object distance (u) in case of a convex lens and answer the questions that follow,
without doing any calculations:
S. No. Object distance u (cm) Image distance v (cm)
1. -90 +18
2. -60 +20
3. -30 +30
4. -20 +60
5. -18 +90
6. -10 +100
(i) What is the focal length of the convex lens? Give reason in support of your answer.
(ii) Write the serial number of that observation which is not correct. How did you arrive
at this conclusion?
(iii) Take an appropriate scale to draw ray diagram for the observation at S.No. 4 and find
the approximate value of magnification.
 SECTION E
23. A student did an experiment with a convex lens. He put an object at different
distances 25cm, 30cm, 40cm, 60cm and 120cm from the lens. In each case he
measured the distance of the image from the lens. His results were 100cm, 24cm,
60cm, 30cm and 40cm, respectively. Unfortunately his results are written in wrong
order:
(i) Rewrite the image distances in the correct order.
(ii) What would be the image distance if the object distance was 90cm?
(iii) Which of the object distances gives the biggest image?
(iv) What is the focal length of this lens?

24. Hold a concave mirror in your hand and direct its reflecting surface towards the sun.
Direct the light reflected by the mirror on to a white card-board held close to the mirror.
Move the card-board back and forth gradually until you find a bright, sharp spot of light
on the board. This spot of light is the image of the sun on the sheet of paper; which is
also termed as “Principal Focus” of the concave mirror.

a) List two applications of concave mirror.

b) If the distance between the mirror and the principal focus is 15 cm, find the
radius of curvature of the mirror.
c) Draw a ray diagram to show the type of image formed when an object is placed
between pole and focus of a concave mirror