R.S.CLASSES
LIGHT - REFLECTION
PRACTICE QUESTIONS
Q.1 A concave mirror of focal length f produces an image n times the size of the object.What
would be the object distance for which the image will be real?
Ans: (n+1/n) f
Q.2 The image formed by a spherical mirror is real, inverted and is of magnification -2. If the
image is at a distance of 30cm from the mirror, where is the object placed? Find the focal length
of the mirror. List two characteristics of the image formed if the object is moved 10cm towards
the mirror.
Ans: u = -15 cm, f= -10cm
Q.3 An object 2cm high is placed at a distance of 16cm from a concave mirror which produces a
real image 3cm high.
(i) Find the position of the image.
(ii) What is the focal length of mirror?
Ans: v = -24 cm, f = - 9.6cm
Q.4 A concave mirror of focal length 10cm is placed at a distance of 35 cm from a wall. How far
from the wall an object be placed so that it's image formed by the mirror falls on the wall?
Ans: 21 cm
Q.5 A 2 cm tall object is placed perpendicular to the principal axis of a concave mirror of focal
length 10cm. The distance of the object from the mirror is 15 cm. Find the nature, position and
size of image formed. Represent the situation with the help of ray diagram.
Ans: v = -30 cm , hi = -4cm
Q.6 A 2 cm high object is placed at a distance of 32 cm from a concave mirror. The image is
real, inverted and 3cm in size. Find the focal length of the mirror and the position where the
image is formed?
Ans: v = - 48cm, f = - 19.2 cm
Q.7 A concave mirror has a focal length of 20cm. At what distance from the mirror should a 4
cm tall object be placed so that it forms an image at a distance of 30 cm from the mirror? Also
calculate the size of the image formed.
Ans: u = -60 cm, hi = -2 cm
Q.8 An object 4cm in height is placed at 15cm in front of a concave mirror of focal length10 cm.
At what distance from the mirror should a screen be placed to obtain a sharp image of the
object. Calculate the height of the image.
Ans: v = -30cm, hi = -8cm
Q.9 A 6cm tall object is placed perpendicular to the principal axis of a concave mirror of focal
length 30cm. The distance of the object from the mirror is 45cm. Use mirror formula to
determine the position, nature and size of the image formed. Also draw labelled ray diagram to
show the image formation in this case.
Ans : f = -90cm, hi = -12 cm
Q.10 A truck uses a convex mirror as view finder whose radius of curvature is 2.0 m. A maruti
car is coming behind the truck at a distance of 10m. What will be the position of the image of the
car and size of the image of the car when observed by the driver of the truck through the convex
mirror?
LIGHT - REFLECTION
PRACTICE QUESTIONS
Q.1 A concave mirror of focal length f produces an image n times the size of the object.What
would be the object distance for which the image will be real?
Ans: (n+1/n) f
Q.2 The image formed by a spherical mirror is real, inverted and is of magnification -2. If the
image is at a distance of 30cm from the mirror, where is the object placed? Find the focal length
of the mirror. List two characteristics of the image formed if the object is moved 10cm towards
the mirror.
Ans: u = -15 cm, f= -10cm
Q.3 An object 2cm high is placed at a distance of 16cm from a concave mirror which produces a
real image 3cm high.
(i) Find the position of the image.
(ii) What is the focal length of mirror?
Ans: v = -24 cm, f = - 9.6cm
Q.4 A concave mirror of focal length 10cm is placed at a distance of 35 cm from a wall. How far
from the wall an object be placed so that it's image formed by the mirror falls on the wall?
Ans: 21 cm
Q.5 A 2 cm tall object is placed perpendicular to the principal axis of a concave mirror of focal
length 10cm. The distance of the object from the mirror is 15 cm. Find the nature, position and
size of image formed. Represent the situation with the help of ray diagram.
Ans: v = -30 cm , hi = -4cm
Q.6 A 2 cm high object is placed at a distance of 32 cm from a concave mirror. The image is
real, inverted and 3cm in size. Find the focal length of the mirror and the position where the
image is formed?
Ans: v = - 48cm, f = - 19.2 cm
Q.7 A concave mirror has a focal length of 20cm. At what distance from the mirror should a 4
cm tall object be placed so that it forms an image at a distance of 30 cm from the mirror? Also
calculate the size of the image formed.
Ans: u = -60 cm, hi = -2 cm
Q.8 An object 4cm in height is placed at 15cm in front of a concave mirror of focal length10 cm.
At what distance from the mirror should a screen be placed to obtain a sharp image of the
object. Calculate the height of the image.
Ans: v = -30cm, hi = -8cm
Q.9 A 6cm tall object is placed perpendicular to the principal axis of a concave mirror of focal
length 30cm. The distance of the object from the mirror is 45cm. Use mirror formula to
determine the position, nature and size of the image formed. Also draw labelled ray diagram to
show the image formation in this case.
Ans : f = -90cm, hi = -12 cm
Q.10 A truck uses a convex mirror as view finder whose radius of curvature is 2.0 m. A maruti
car is coming behind the truck at a distance of 10m. What will be the position of the image of the
car and size of the image of the car when observed by the driver of the truck through the convex
mirror?
