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Thursday, 15 December 2011

Science for 10th student Maharashtra board


Question 1:   The change in focal length of an eye lens to focus the image of objects at varying distances is done by the action of ________.

1.
pupil
2.
ciliary muscles
3.
retina
4.
blind spot

Question 2:   Far point of a normal eye is situated at _________.

1.
25 cm
2.
infinity
3.
50 cm
4.
400 cm
Question3:   Power of a lens is expressed in
1.
dioptre
2.
cm
3.
metre
4.
millimetre

Question 4:   1 D is the power of a lens of focal length ______ cm.

1.
100
2.
10
3.
1/100
4.
1/10

Question 5:   Hypermetropia is rectified by using

1.
convex lens
2.
concave lens
3.
cylindrical lens
4.
progressive lens

Question 6:   Reciprocal of focal length in metres is known as the ______ of a lens.

1.
focus
2.
power
3.
power of accommodation
4.
far point
Question7:   The power of a convex lens of focal length 50 cm is ______.
1.
+ 2 D
2.
- 2 D
3.
50 D
4.
- 5 D
Question8:   Two lenses having powers +2D and -4D respectively are put together. Power of the combination would be
1.
-2 D
2.
+2 D
3.
-4 D
4.
+4 D

Question9:   The fluid between the retina and the lens is called _______.
1.
aqueous humour
2.
vitreous humour
3.
aqua
4.
humus
Question10:   Two thin lenses of power +5D and -2D are put in contact with each other. Focal length of the combination is
1.
+3 m
2.
-3 m
3.
0.33 m
4.
-0.33 m
Question11:   The focal length of a lens whose power is -1.5 D is _______.
1.
-66.66 cm
2.
+ 1.5 m
3.
+ 66.66 cm
4.
-1.5 m
Question12:   The lens formula in cartesian frame is ______________.
1.
image
2.
image
3.
image
4.
image
Question13:   The part of the lens through which the ray of light passes without suffering deviation is called ________.
1.
optical centre
2.
focus
3.
centre of curvature
4.
pole
Question14:   Convex lens always gives a real image if the object is situated beyond _______.
1.
optical centre
2.
centre of curvature
3.
focus
4.
radius of curvature
Question15:   Parallel rays of light entering a convex lens always converge at _______.
1.
centre of curvature
2.
the principal focus
3.
optical centre
4.
the focal plane
Question16:   Where should an object be placed so that a real and inverted image of the same size is obtained, using a convex lens?
1.
Between O and F
2.
At F
3.
At 2 F
4.
At infinity
Question17:   SI unit of the power of a lens is ___________.
1.
dioptre
2.
cm
3.
metre
4.
watt
Question18:   In a simple microscope lens used is __________.
1.
biconvex
2.
biconcave
3.
plano convex
4.
cylindrical
Question19:   A convex lens is called _________.
1.
converging lens
2.
diverging lens
3.
both converging and diverging lens
4.
refracting lens
Question20:   A positive magnification greater than unity indicates _____________________.
1.
real image
2.
virtual image
3.
neither real not virtual image
4.
distorted image
Question21: The power of a convex lens of focal length 50 cm is ______.
1.
+ 2D
2.
- 2D
3.
50 D
4.
- 5D
Question22:   Real images formed by single convex lenses are always ________________.
1.
on the same side of the lens as the object
2.
inverted
3.
erect
4.
smaller than the object
Question23:   An object is placed 12 cm from a convex lens whose focal length is 10 cm. The image must be.
1.
virtual and enlarged
2.
virtual and reduced in size
3.
real and reduced in size
4.
real and enlarged
Question24:   The image produced by a concave lens is ________.
1.
always virtual and enlarged
2.
always virtual and reduced in size
3.
always real
4.
sometimes real, sometimes virtual
Question25:   A virtual image is formed by _______.
1.
a slide projector in a cinema hall
2.
the ordinary camera
3.
a simple microscope
4.
telescope
Question26:   An object is placed 25 cm from a convex lens whose focal length is 10 cm. The image distance is ________ cm.
1.
50 cm
2.
16.66 cm
3.
6.66 cm
4.
10 cm
Question27:   The least distance of distinct vision is ______.
1.
25 cm
2.
25 m
3.
0.25 cm
4.
2.5 m

Question28:   A convex lens has a focal length of 20 cm. Its power in dioptres is ___________.
1.
2
2.
5
3.
0.5
4.
0.2
Question29:   The phenomenon by which the incident light falling on a surface is sent back into the same medium is known as ________.
1.
polarization
2.
reflection
3.
refraction
4.
absorption
Question30:   The image formed by a plane mirror is always _______.
1.
real and erect
2.
virtual and erect
3.
real and inverted
4.
virtual and inverted
Question31:   The centre of the sphere of which the spherical mirror forms a part is called ____________.
1.
centre of curvature
2.
focus
3.
pole
4.
vertex
Question32:   The focus of a concave mirror is ________.
1.
real
2.
virtual
3.
undefined
4.
at the pole
Question33:   A converging mirror is known as ________.
1.
convex mirror
2.
plane mirror
3.
concave mirror
4.
cylindrical mirror
Question34:   The relation between the focal length and radius of curvature of a mirror is _______.
1.
image
2.
R + 2 = f
3.
f = R/2
4.
f = 2 R
Question35:   An image formed by a convex mirror is always ________.
1.
virtual, erect and diminished
2.
virtual, real and magnified
3.
real, inverted and diminished
4.
real, erect and magnified
Question36:   If the image formed by a concave mirror is virtual, erect and magnified, then the object is placed __________.
1.
between the pole of the mirror and the focus
2.
beyond the centre of curvature
3.
at the centre of curvature
4.
at the focus
Question37:   Dentists use a _____________ to focus light on the tooth of a patient.
1.
concave mirror
2.
convex mirror
3.
plane mirror
4.
cylindrical mirror
Question38:   What is the value of q in the following diagram?
image
1.
30o
2.
45o
3.
90o
4.
60o
Question39:   What is the angle between the incident and reflected rays when a ray of light is incident normally on a plane mirror?
1.
90o
2.
45o
3.
180o
4.
0
Question40:   Name the type of image that can be obtained on a screen.
1.
Virtual
2.
Real
3.
Diverging
4.
Converging
Question41:   A ray of light is incident on a plane mirror and the angle of incidence is 25o. What is the angle of reflection?
1.
0
2.
50o
3.
90o
4.
25o
Question42:   Which of the following is used to make a periscope?
1.
Concave mirror
2.
Convex mirror
3.
Plane mirror
4.
Lens
Question43:   Which mirror has a wider field of view?
1.
Convex mirror
2.
Concave mirror
3.
Plane mirror
4.
Cylindrical mirror
Question44:   The focal length of a concave mirror is 15 cm. What is its radius of curvature?
1.
15 cm
2.
30 cm
3.
7.5 cm
4.
45 cm
Question45:   The focal length of a mirror is 15 cm. Identify the type of mirror.
1.
Concave mirror
2.
Plane mirror
3.
Convex mirror
4.
Cylindrical mirror
Question46:   A ray of light passing through the _______ retraces its path.
1.
focus
2.
centre of curvature
3.
pole
4.
vertex
Question47:   When an object is placed at the focus of a concave mirror, the image will be formed at ________.
1.
infinity
2.
focus
3.
centre of curvature
4.
pole
Question48:   An object of size 2.0 cm is placed perpendicular to the principal axis of a concave mirror. The distance of the object from the mirror equals to the radius of curvature. The size of the image will be ______________.
1.
0.5 cm
2.
1.5 cm
3.
1.0 cm
4.
2.0 cm
Question49:   If an incident ray passes through the centre of curvature of a spherical mirror, the reflected ray will __________________.
1.
pass through the focus
2.
pass through the centre of curvature
3.
pass through the pole
4.
retrace its path

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