NUMERICALS BASED ON CONVEX AND CONCAVE MIRROR

1. Find the focal length of a convex mirror of radius of curvature 1m.

2. Focal length of a convex mirror is 50 cm. What is its radius of curvature?
3. Radius of curvature of a concave mirror is 25 cm. What is its focal length?
4. A concave mirror produces 10 cm long image of an object of height of 2cm. What is
the magnification produced?
5. An object 1 cm high is held near a concave mirror of magnification 10. How tall will
be the image?
6. An object 4 cm in size is placed at a distance of 25 cm from a concave mirror of focal
length 15 cm. Find the position, nature and height of the image.
7. A converging mirror forms a real image of height 4 cm, of an object of height 1 cm
placed 20 cm away from the mirror. Calculate the image distance. What is the focal
length of the mirror?
8. A 4.5 cm needle is placed 12 cm away from a convex mirror of focal length 15 cm.
Give the location of the image and the magnification. Describe what happens as the
needle is moved farther from the mirror.
9. An arrow 2.5 cm high is placed at a distance of 25 cm from a diverging mirror of
focal length 20 cm., Find the nature, position and size of the image formed.
10. The image formed by a convex mirror of focal length 20cm is a quarter of the object.
What is the distance of the object from the mirror?
11. Find the size, nature and position of image formed by a concave mirror, when an
object of size 1cm is placed at a distance of 15cm. Given focal length of mirror is
10cm.
12. An object 2cm high is placed at a distance of 16cm from a concave mirror, which
produces 3cm high inverted image. What is the focal length of the mirror? Also, find
the position of the image.
13. An erect image 3 times the size of the object is obtained with a concave mirror of
radius of curvature 36cm. What is the position of the object?
14. A 2.5cm candle is placed 12 cm away from a convex mirror of focal length 30cm.
Give the location of the image and the magnification.
15. An object is placed in front of a concave mirror of focal length 20cm. The image
formed is 3 times the size of the object. Calculate two possible distances of the object
from the mirror.
16. The image formed by a convex mirror is virtual, erect and smaller in size. Illustrate
with figure.
Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 12 -
17. A concave mirror produces a real image 10mm tall, of an object 2.5mm tall placed at
5cm from the mirror. Calculate focal length of the mirror and the position of the
image.
18. An object is placed at a large distance in front of a convex mirror of radius of
curvature 40cm. How far is the image behind the mirror?
19. An object is placed 15cm from a convex mirror of radius of curvature 90cm.
Calculate position of the image and its magnification.
20. The image formed by a convex mirror of focal length 30cm is a quarter of the object.
What is the distance of the object from the mirror?
21. When an object is placed at a distance of 60cm from a convex mirror, the
magnification produced is 1/2. Where should the object be place to get a
magnification of 1/3?
22. An object is placed 18cm front of a mirror. If the image is formed at 4cm to the right
of the mirror. Calculate its focal length. Is the mirror convex or concave? What is the
nature of the image? What is the radius of curvature of the mirror?
23. A convex mirror used for rear view on an automobile has a radius of curvature of 3m.
If a bus is located at 5m from this mirror, find the position, nature and magnification
of the image.
24. An object 3cm high is held at a distance of 50cm from a diverging mirror of focal
length 25cm. Find the nature, position and size of the image formed.
25. An converging mirror of focal length 20cm forms an image which is two times the
size of the object. Calculate two possible distances of the object from the mirror.
26. The linear magnification of a convex mirror of focal length 15cm is 1/3. What is the
distance of the object from the focus of the mirror?
27. The focal length of a convex mirror is 12.5 cm. How far is its centre of curvature (i)
from the pole (ii) from the focus.
28. Find the focal length of a concave mirror that produces four times larger real image of
an object held at 5cm from the mirror.
29. An object is held at 30cm in front of a convex mirror of focal length 15cm. At what
distance from the convex mirror should a plane mirror be held so that images in the
two images coincide with each other?
30. Draw any three ray diagrams to show how the size and nature of image of an object
change when it move from centre of curvature of concave mirror towards the pole of
the mirror.

Prepared by: M. S. KumarSwamy, TGT(Maths) Page - 13 -