Ray Optics- 1 Practice Questions - DPP for NEET

 Page 1


DIRECTIONS (Q.1-Q.22) : There are 22 multiple choice
questions. Each question has 4 choices (a), (b), (c) and (d), out
of which ONLY ONE choice is correct.
Q.1 Find the number of images formed by two mutually
perpendicular mirrors –
(a)3 (b)4 (c)1 (d)2
Q.2 The angle q between two plane mirrors producing five
images of a given object is given by.
(a) 30º
 
£ q £ 72º (b) 45º
 
£ q £ 72º
(c) 60º
 
£ q £ 72º (d) 15º
 
£ q £ 72º
Q.3 Two mirrors are inclined at an angle of 50º. Then what is
the number of images formed for an object placed in be-
tween the mirrors ?
(a)3 (b)6 (c)1 (d)7
Q.4 Two plane mirrors are inclined at an angle q. A ray of light
is incident on one mirror at an angle of incidence i. The
ray is reflected from this mirror, falls on the second mir-
ror from where it is reflected parallel to the first mirror.
What is the value of i, the angle of incidence in terms q ?
(a)2q - 90º (b)4q - 90º
(c) q - 90º (d)3q - 90º
Q.5 A girl stands at a distance 30 cm from the mirror. She is
able to see her erect image but of 1/5 height of actual
height. The mirror will be :
(a) plane mirror (b) concave mirror
(c) convex mirror (d) plane convex mirror
Page 2


DIRECTIONS (Q.1-Q.22) : There are 22 multiple choice
questions. Each question has 4 choices (a), (b), (c) and (d), out
of which ONLY ONE choice is correct.
Q.1 Find the number of images formed by two mutually
perpendicular mirrors –
(a)3 (b)4 (c)1 (d)2
Q.2 The angle q between two plane mirrors producing five
images of a given object is given by.
(a) 30º
 
£ q £ 72º (b) 45º
 
£ q £ 72º
(c) 60º
 
£ q £ 72º (d) 15º
 
£ q £ 72º
Q.3 Two mirrors are inclined at an angle of 50º. Then what is
the number of images formed for an object placed in be-
tween the mirrors ?
(a)3 (b)6 (c)1 (d)7
Q.4 Two plane mirrors are inclined at an angle q. A ray of light
is incident on one mirror at an angle of incidence i. The
ray is reflected from this mirror, falls on the second mir-
ror from where it is reflected parallel to the first mirror.
What is the value of i, the angle of incidence in terms q ?
(a)2q - 90º (b)4q - 90º
(c) q - 90º (d)3q - 90º
Q.5 A girl stands at a distance 30 cm from the mirror. She is
able to see her erect image but of 1/5 height of actual
height. The mirror will be :
(a) plane mirror (b) concave mirror
(c) convex mirror (d) plane convex mirror
2
DPP/ P 49
Q.6 An object is placed at a distance of 50 cm from a convex
mirror. A plane mirror is placed in front of the convex
mirror in such a way that it convers half of the convex
mirror. If the distance between object and plane mirror is
30 cm then there is no parallax between the images formed
by two mirrors , the radius of curvature of convex mirror
will be :
(a) 50 cm (b) 25 cm (c) 12.5 cm (d) 100cm
Q.7 Two plane mirrors are inclined at an angle of 30º. Then the
first four images of an object O placed between the two
mirrors are correctly represented by
(a)
I
2
I
1
I
4
I
3
M
1
M
2
(b)
I
2
I
1
I
4
I
3
M
1
M
2
(c)
I
2
I
1
I
3
I
4
M
1
M
2 (d)
I
2
I
1
I
3
I
4
M
1
M
2
Q.8 The plane of a mirror makes an angle of 30º with horizontal.
If a vertical ray is incident on a mirror, then what is the
angle between mirror and reflected ray ?
(a) 60º (b) 90º (c) 45º (d) 30º
Q.9 Two plane mirrors are placed at an angle a so that a ray paral-
lel to one mirror gets reflected parallel to the second mirror
after two consecutive reflections. The value of a will be
(a) 30º (b) 60º (c) 75º (d) 90º
Q.10 A 0.2 cm high object is placed 15 cm from a concave mirror
of focal length 5 cm. Find position and size of the image.
(a) 7.5 cm, 0.1 cm. (b) 7.5 cm, 0.4 cm.
(c) 10.0 cm, 0.5 cm. (d) 7.5 cm, 0.4 cm.
Q.11 A 0.5 cm high object is placed at 30 cm from a convex
mirror whose focal length is 20 cm. Find the position and
size of the image.
(a) 12 cm, 0.2 cm (b) 18 cm, 0.2 cm
(c) 6 cm, 0.5 cm (d) 5 cm, 0.1 cm
Q.12 There is a convex mirror of radius 50 cm. The image of a
point at a distance 50 cm from the pole of mirror on its
axis will be formed at :
(a) infinity
(b) pole
50 cm
O
C · ·
50 cm
/ / / /////////////////////////
(c) focus
(d) 16.67 cm behind the mirror
Q.13 A particle is moving at a constant speed v
0
 from a large
distance towards a concave mirror of radius R along its
principle axis. Find the speed of the image formed by the
mirror as a function of the distance u of the particles from
the mirror.
(a)
2
R
2uR
æö
ç÷
èø -
.v
0
(b)
2
R
2uR
æö
ç÷
èø +
.v
0
(c)
2
2R
2uR
æö
ç÷
èø -
.v
0
(d) None of these
Q.14 A short linear object of length b lies along the axis of a
concave mirror of focal length f at a distance u from the
pole of the mirror. Find the approximate size of the image.
(a) b 
2
f
uf
æö
ç÷
èø
-
(b) b 
2
f
uf
æö
ç÷
èø
+
(c) b 
2
2f
uf
æö
ç÷
èø
-
(d) None of these
Q.15 The relation between the linear magnification m, the object
distance u and the focal length f  for a spherical mirror is
(a)
fu
m
f
-
=
(b)
f
m
fu
=
-
(c)
fu
m
f
+
=
(d)
f
m
fu
=
+
Page 3


DIRECTIONS (Q.1-Q.22) : There are 22 multiple choice
questions. Each question has 4 choices (a), (b), (c) and (d), out
of which ONLY ONE choice is correct.
Q.1 Find the number of images formed by two mutually
perpendicular mirrors –
(a)3 (b)4 (c)1 (d)2
Q.2 The angle q between two plane mirrors producing five
images of a given object is given by.
(a) 30º
 
£ q £ 72º (b) 45º
 
£ q £ 72º
(c) 60º
 
£ q £ 72º (d) 15º
 
£ q £ 72º
Q.3 Two mirrors are inclined at an angle of 50º. Then what is
the number of images formed for an object placed in be-
tween the mirrors ?
(a)3 (b)6 (c)1 (d)7
Q.4 Two plane mirrors are inclined at an angle q. A ray of light
is incident on one mirror at an angle of incidence i. The
ray is reflected from this mirror, falls on the second mir-
ror from where it is reflected parallel to the first mirror.
What is the value of i, the angle of incidence in terms q ?
(a)2q - 90º (b)4q - 90º
(c) q - 90º (d)3q - 90º
Q.5 A girl stands at a distance 30 cm from the mirror. She is
able to see her erect image but of 1/5 height of actual
height. The mirror will be :
(a) plane mirror (b) concave mirror
(c) convex mirror (d) plane convex mirror
2
DPP/ P 49
Q.6 An object is placed at a distance of 50 cm from a convex
mirror. A plane mirror is placed in front of the convex
mirror in such a way that it convers half of the convex
mirror. If the distance between object and plane mirror is
30 cm then there is no parallax between the images formed
by two mirrors , the radius of curvature of convex mirror
will be :
(a) 50 cm (b) 25 cm (c) 12.5 cm (d) 100cm
Q.7 Two plane mirrors are inclined at an angle of 30º. Then the
first four images of an object O placed between the two
mirrors are correctly represented by
(a)
I
2
I
1
I
4
I
3
M
1
M
2
(b)
I
2
I
1
I
4
I
3
M
1
M
2
(c)
I
2
I
1
I
3
I
4
M
1
M
2 (d)
I
2
I
1
I
3
I
4
M
1
M
2
Q.8 The plane of a mirror makes an angle of 30º with horizontal.
If a vertical ray is incident on a mirror, then what is the
angle between mirror and reflected ray ?
(a) 60º (b) 90º (c) 45º (d) 30º
Q.9 Two plane mirrors are placed at an angle a so that a ray paral-
lel to one mirror gets reflected parallel to the second mirror
after two consecutive reflections. The value of a will be
(a) 30º (b) 60º (c) 75º (d) 90º
Q.10 A 0.2 cm high object is placed 15 cm from a concave mirror
of focal length 5 cm. Find position and size of the image.
(a) 7.5 cm, 0.1 cm. (b) 7.5 cm, 0.4 cm.
(c) 10.0 cm, 0.5 cm. (d) 7.5 cm, 0.4 cm.
Q.11 A 0.5 cm high object is placed at 30 cm from a convex
mirror whose focal length is 20 cm. Find the position and
size of the image.
(a) 12 cm, 0.2 cm (b) 18 cm, 0.2 cm
(c) 6 cm, 0.5 cm (d) 5 cm, 0.1 cm
Q.12 There is a convex mirror of radius 50 cm. The image of a
point at a distance 50 cm from the pole of mirror on its
axis will be formed at :
(a) infinity
(b) pole
50 cm
O
C · ·
50 cm
/ / / /////////////////////////
(c) focus
(d) 16.67 cm behind the mirror
Q.13 A particle is moving at a constant speed v
0
 from a large
distance towards a concave mirror of radius R along its
principle axis. Find the speed of the image formed by the
mirror as a function of the distance u of the particles from
the mirror.
(a)
2
R
2uR
æö
ç÷
èø -
.v
0
(b)
2
R
2uR
æö
ç÷
èø +
.v
0
(c)
2
2R
2uR
æö
ç÷
èø -
.v
0
(d) None of these
Q.14 A short linear object of length b lies along the axis of a
concave mirror of focal length f at a distance u from the
pole of the mirror. Find the approximate size of the image.
(a) b 
2
f
uf
æö
ç÷
èø
-
(b) b 
2
f
uf
æö
ç÷
èø
+
(c) b 
2
2f
uf
æö
ç÷
èø
-
(d) None of these
Q.15 The relation between the linear magnification m, the object
distance u and the focal length f  for a spherical mirror is
(a)
fu
m
f
-
=
(b)
f
m
fu
=
-
(c)
fu
m
f
+
=
(d)
f
m
fu
=
+
DPP/ P 49
3
Q.16 An object of length 1 cm is placed at a distance of 15 cm
from a concave mirror of focal length 10 cm. The nature
and size of the image are
(a) real, inverted, 1.0 cm (b) real, inverted, 2.0 cm
(c) virtual, erect, 0.5 cm (d) virtual, erect, 1.0 cm
Q.17In an experiment to determine the focal length
(f ) of a concave mirror by the u - v method, a student places
the object pin  A on the principal axis at a distance x from
the pole P. The student looks at the pin and its inverted
image from a distance keeping his/her eye in line with PA.
When the student shifts his/her eye towards left, the image
appears to the right of the object pin. Then,
(a) x  <  f (b) f<x<2f (c) x  =  2f (d) x  >  2f
Q.18 Two plane mirrors are inclined to each other at some angle.
A ray of light incident at 30º on one, after reflection from
the other retraces its path. The angle between the mirrors
is
(a) 30º (b) 45º (c) 60º (d) 90º
Q.19A convex mirror is used to form the image of an object.
Which of the following statements is wrong ?
(a) The image lies between the pole and the focus
(b) The image is diminished in size
(c) The image is erect
(d) The image is real
Q.20 A point source of light B is placed at a distance L in front
of the centre of a mirror of width 'd' hung vertically  on a
wall. A man walks in front of the mirror along a line parallel
to the mirror at a distance 2L from it as shown in fig. The
greatest distance over which he can see the image of the
light source in the mirror is
L
2L
d
B
(a) d/2 (b) d (c)2d (d)3d
Q.21 A concave mirror of focal length f
0
(in magnitude) produces
a real image n time the size of the object. What is the
distance of the object from the mirror?
(a)
0
(n 1)
f
n
-+
(b)
0
(n 1)
f
n
+
(c)
(n 1)
n
-
f
0
(d) 
2
0
(n 1)
f
n
-+
Q.22The focal length of a concave mirror is 30 cm. Find the
position of the object in front of the mirror, so that the
image is three times the size of the object.
(a) 20 cm (only) (b) 40 cm (only)
(c) 30 cm (only) (d) 20 cm or 40 cm
DIRECTIONS (Q.23-Q.25) : In the following questions,
more than one of the answers  given are correct. Select the
correct answers and mark it according to the following
codes:
Codes :
(a) 1, 2 and 3 are correct (b) 1 and 2 are correct
(c) 2 and 4 are correct (d) 1 and 3 are correct
Q.23 A plane mirror reflecting a ray of incident light is rotated
through an angle q about an axis through the point of
incidence in the plane of the mirror perpendicular to the
plane of incidence, then
(1) The reflected ray rotates through an angle 2q
(2) The incident ray is fixed
(3) The reflected ray does not rotate
(4) The reflected ray rotates through an angle q
Q.24 The light reflected by a plane mirror will not form a real
image
(1) If the rays incident on the mirror are diverging
(2) Under no circumstances
(3) If the object is real
(4) If the rays incident on the mirror are converging
Page 4


DIRECTIONS (Q.1-Q.22) : There are 22 multiple choice
questions. Each question has 4 choices (a), (b), (c) and (d), out
of which ONLY ONE choice is correct.
Q.1 Find the number of images formed by two mutually
perpendicular mirrors –
(a)3 (b)4 (c)1 (d)2
Q.2 The angle q between two plane mirrors producing five
images of a given object is given by.
(a) 30º
 
£ q £ 72º (b) 45º
 
£ q £ 72º
(c) 60º
 
£ q £ 72º (d) 15º
 
£ q £ 72º
Q.3 Two mirrors are inclined at an angle of 50º. Then what is
the number of images formed for an object placed in be-
tween the mirrors ?
(a)3 (b)6 (c)1 (d)7
Q.4 Two plane mirrors are inclined at an angle q. A ray of light
is incident on one mirror at an angle of incidence i. The
ray is reflected from this mirror, falls on the second mir-
ror from where it is reflected parallel to the first mirror.
What is the value of i, the angle of incidence in terms q ?
(a)2q - 90º (b)4q - 90º
(c) q - 90º (d)3q - 90º
Q.5 A girl stands at a distance 30 cm from the mirror. She is
able to see her erect image but of 1/5 height of actual
height. The mirror will be :
(a) plane mirror (b) concave mirror
(c) convex mirror (d) plane convex mirror
2
DPP/ P 49
Q.6 An object is placed at a distance of 50 cm from a convex
mirror. A plane mirror is placed in front of the convex
mirror in such a way that it convers half of the convex
mirror. If the distance between object and plane mirror is
30 cm then there is no parallax between the images formed
by two mirrors , the radius of curvature of convex mirror
will be :
(a) 50 cm (b) 25 cm (c) 12.5 cm (d) 100cm
Q.7 Two plane mirrors are inclined at an angle of 30º. Then the
first four images of an object O placed between the two
mirrors are correctly represented by
(a)
I
2
I
1
I
4
I
3
M
1
M
2
(b)
I
2
I
1
I
4
I
3
M
1
M
2
(c)
I
2
I
1
I
3
I
4
M
1
M
2 (d)
I
2
I
1
I
3
I
4
M
1
M
2
Q.8 The plane of a mirror makes an angle of 30º with horizontal.
If a vertical ray is incident on a mirror, then what is the
angle between mirror and reflected ray ?
(a) 60º (b) 90º (c) 45º (d) 30º
Q.9 Two plane mirrors are placed at an angle a so that a ray paral-
lel to one mirror gets reflected parallel to the second mirror
after two consecutive reflections. The value of a will be
(a) 30º (b) 60º (c) 75º (d) 90º
Q.10 A 0.2 cm high object is placed 15 cm from a concave mirror
of focal length 5 cm. Find position and size of the image.
(a) 7.5 cm, 0.1 cm. (b) 7.5 cm, 0.4 cm.
(c) 10.0 cm, 0.5 cm. (d) 7.5 cm, 0.4 cm.
Q.11 A 0.5 cm high object is placed at 30 cm from a convex
mirror whose focal length is 20 cm. Find the position and
size of the image.
(a) 12 cm, 0.2 cm (b) 18 cm, 0.2 cm
(c) 6 cm, 0.5 cm (d) 5 cm, 0.1 cm
Q.12 There is a convex mirror of radius 50 cm. The image of a
point at a distance 50 cm from the pole of mirror on its
axis will be formed at :
(a) infinity
(b) pole
50 cm
O
C · ·
50 cm
/ / / /////////////////////////
(c) focus
(d) 16.67 cm behind the mirror
Q.13 A particle is moving at a constant speed v
0
 from a large
distance towards a concave mirror of radius R along its
principle axis. Find the speed of the image formed by the
mirror as a function of the distance u of the particles from
the mirror.
(a)
2
R
2uR
æö
ç÷
èø -
.v
0
(b)
2
R
2uR
æö
ç÷
èø +
.v
0
(c)
2
2R
2uR
æö
ç÷
èø -
.v
0
(d) None of these
Q.14 A short linear object of length b lies along the axis of a
concave mirror of focal length f at a distance u from the
pole of the mirror. Find the approximate size of the image.
(a) b 
2
f
uf
æö
ç÷
èø
-
(b) b 
2
f
uf
æö
ç÷
èø
+
(c) b 
2
2f
uf
æö
ç÷
èø
-
(d) None of these
Q.15 The relation between the linear magnification m, the object
distance u and the focal length f  for a spherical mirror is
(a)
fu
m
f
-
=
(b)
f
m
fu
=
-
(c)
fu
m
f
+
=
(d)
f
m
fu
=
+
DPP/ P 49
3
Q.16 An object of length 1 cm is placed at a distance of 15 cm
from a concave mirror of focal length 10 cm. The nature
and size of the image are
(a) real, inverted, 1.0 cm (b) real, inverted, 2.0 cm
(c) virtual, erect, 0.5 cm (d) virtual, erect, 1.0 cm
Q.17In an experiment to determine the focal length
(f ) of a concave mirror by the u - v method, a student places
the object pin  A on the principal axis at a distance x from
the pole P. The student looks at the pin and its inverted
image from a distance keeping his/her eye in line with PA.
When the student shifts his/her eye towards left, the image
appears to the right of the object pin. Then,
(a) x  <  f (b) f<x<2f (c) x  =  2f (d) x  >  2f
Q.18 Two plane mirrors are inclined to each other at some angle.
A ray of light incident at 30º on one, after reflection from
the other retraces its path. The angle between the mirrors
is
(a) 30º (b) 45º (c) 60º (d) 90º
Q.19A convex mirror is used to form the image of an object.
Which of the following statements is wrong ?
(a) The image lies between the pole and the focus
(b) The image is diminished in size
(c) The image is erect
(d) The image is real
Q.20 A point source of light B is placed at a distance L in front
of the centre of a mirror of width 'd' hung vertically  on a
wall. A man walks in front of the mirror along a line parallel
to the mirror at a distance 2L from it as shown in fig. The
greatest distance over which he can see the image of the
light source in the mirror is
L
2L
d
B
(a) d/2 (b) d (c)2d (d)3d
Q.21 A concave mirror of focal length f
0
(in magnitude) produces
a real image n time the size of the object. What is the
distance of the object from the mirror?
(a)
0
(n 1)
f
n
-+
(b)
0
(n 1)
f
n
+
(c)
(n 1)
n
-
f
0
(d) 
2
0
(n 1)
f
n
-+
Q.22The focal length of a concave mirror is 30 cm. Find the
position of the object in front of the mirror, so that the
image is three times the size of the object.
(a) 20 cm (only) (b) 40 cm (only)
(c) 30 cm (only) (d) 20 cm or 40 cm
DIRECTIONS (Q.23-Q.25) : In the following questions,
more than one of the answers  given are correct. Select the
correct answers and mark it according to the following
codes:
Codes :
(a) 1, 2 and 3 are correct (b) 1 and 2 are correct
(c) 2 and 4 are correct (d) 1 and 3 are correct
Q.23 A plane mirror reflecting a ray of incident light is rotated
through an angle q about an axis through the point of
incidence in the plane of the mirror perpendicular to the
plane of incidence, then
(1) The reflected ray rotates through an angle 2q
(2) The incident ray is fixed
(3) The reflected ray does not rotate
(4) The reflected ray rotates through an angle q
Q.24 The light reflected by a plane mirror will not form a real
image
(1) If the rays incident on the mirror are diverging
(2) Under no circumstances
(3) If the object is real
(4) If the rays incident on the mirror are converging
4
DPP/ P 49
Q.25 Which of the following form(s) a virtual and erect image
for all positions of the object?
(1) Convex lens (2) Concave lens
(3) Convex mirror (4) Concave mirror
DIRECTIONS (Q.26-Q.27) : Read the passage given below
and answer the questions that follows :
A plane mirror (M
1
) and a concave mirror
(M
2
) of focal length 10 cm are arranged as
shown in figure. An object is kept at origin.
Answer the following questions. (Consider
image formed by single reflection in all
cases)
45°
M
2
20 cm
10 cm
Y
O
X
M
1
Q.26 The co-ordinates of image formed by plane mirror are
(a) (–20 cm, 0) (b) (10 cm, – 60 cm)
(c) (10 cm, –10 cm) (d) (10 cm, 10 cm)
Q.27 The co-ordinates of image formed by concave mirror are
(a) (10 cm, – 40 cm) (b) (10 cm, – 60 cm)
(c) (10 cm, 8 cm) (d) None of these
DIRECTIONS (Qs. 28-Q.30) : Each of these questions contains
two statements: Statement-1 (Assertion) and Statement-2
(Reason). Each of these questions has four alternative choices,
only one of which is the correct answer. You have to select the
correct choice.
(a) Statement-1 is True, Statement-2 is True; Statement-2 is a
correct explanation for  Statement-1.
(b) Statement-1 is True, Statement-2 is True; Statement-2 is
NOT a correct explanation for Statement-1.
(c) Statement -1 is False, Statement-2 is True.
(d) Statement -1 is True, Statement-2 is False.
Q.28 Statement-1: The mirrors used in search lights are
parabolic and not concave spherical.
Statement-2: In a concave spherical mirror the image
formed is always virtual.
Q.29 Statement-1: When an object is placed between two plane
parallel mirors, then all the images found are of different
intensity.
Statement-2: In case of plane parallel mirrors, only two
images are possible.
Q.30 Statement-1: The size of the mirror doesn't affect the
nature of the image.
Statement-2: Small mirror always forms a virtual image.