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# Test: Ray Optics - 1

## 25 Questions MCQ Test Science Class 10 | Test: Ray Optics - 1

Description
This mock test of Test: Ray Optics - 1 for UPSC helps you for every UPSC entrance exam. This contains 25 Multiple Choice Questions for UPSC Test: Ray Optics - 1 (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Ray Optics - 1 quiz give you a good mix of easy questions and tough questions. UPSC students definitely take this Test: Ray Optics - 1 exercise for a better result in the exam. You can find other Test: Ray Optics - 1 extra questions, long questions & short questions for UPSC on EduRev as well by searching above.
QUESTION: 1

### A mirror forms a virtual image of a real object.

Solution:

The image in a plane mirror forms virtual and erect image and appears to be as far behind the mirror as the object is in front of the mirror. A diverging lens or a convex mirror forms a virtual image.A virtual image is produced by a concave mirror when the object is placed inside the focal length of the mirror.

QUESTION: 2

Solution:
QUESTION: 3

### The angle of reflection is the angle between

Solution:

Angle of reflection is the angle between a reflected ray and the normal drawn at the point of incidence to a reflecting surface.

QUESTION: 4

An object is placed at the centre of curvature of a concave mirror. The distance between its image and the pole is

Solution:

When the object is placed at the center of curvature, the image is formed at the center of curvature and we know that the relation between radius of curvature and focal length is R= 2F ( R is used to show radius of curvature And F is the focal length ) if you will notice the its ray diagram then u could see that radius of curvature is always twice of Focal length.

QUESTION: 5

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 the radius of curvature. The size of the image will be

Solution:

The size of the image will  be 2.0 cm.
V=U(given)
m=-v/u
m= - 1
m=h`/h
-1=h`/2
h`=-2
h=2cm

QUESTION: 6

The magnification m of an image formed by a spherical mirror is negative. It means, the image is

Solution:

For spherical mirrors,

m = - v/u

‘m’ is negative when both ‘v’ and ‘u’ have negative values. That is both object and image are on the same side.

So, the correct option is d. The image is inverted, since, it is real.

QUESTION: 7

A point object is placed on the principal axis of a spherical mirror. The object-distance u is

Solution:

Option ( a) is the correct answer. As the object is always placed on the left side of the mirror and according to the sign convention, it has negative value for 'so axis.

Therefore, spherical mirrors have only one reflecting surface and it will be negative only.

QUESTION: 8

= R/2 is valid

Solution:

The relation f = R/2 is applicable only for mirrors. For lenses, you have to use the lens makers formula.

QUESTION: 9

A ray of light is incident on a concave mirror. If it is parallel to the principal axis, the reflected ray will

Solution:
QUESTION: 10

If an incident ray passes through the centre of curvature of a spherical mirror, the reflected ray will

Solution:

An incident ray which passes through the centre of curvature C of the mirror is reflected back along it's own path ( since it is normally incident on the mirror) .

QUESTION: 11

To get an image larger than the object, one can use

Solution:

A convex mirror never forms an image larger than the original object, whereas a concave mirror can form an image larger than the object between the centre of curvature and the point of focus.

QUESTION: 12

A ray of light travelling in air falls obliquely on the surface of a calm pond. It will

Solution:

The light ray bends towards the normal as it travels from a rarer medium of air to a denser medium of water, under goes refraction. Refraction is due to change in the speed of light as it enters from one transparent medium to another. The speed of light increases in rarer medium and decreases in denser medium.

QUESTION: 13

A ray of light goes from a medium of refractive index μ1 to a medium of refractive index μ2. Theangle of incidence is i and the angle of refraction is r. Then, sin i/sin r is equal to

Solution:

Refractive index, also called index of refraction, measure  of the bending of a ray of light when passing from one medium into another. As per Snell's law and the given information ;

QUESTION: 14

A thin lens and a spherical mirror have a focal length of + 15 cm each.

Solution:

According to sign convention distances and points are given their positive or negative sign on the basis of direction of propagation of incident Ray and the focus of both convex mirror and lens are in the front of propagating incident Ray of light so it is taken as positive

QUESTION: 15

A convex lens

Solution:
QUESTION: 16

A convex lens forms a virtual image when an object is placed at a distance of 18 cm from it. The focal length must be

Solution:

A virtual image of an object is formed by a convex lens only when the object is placed between the lens and the focus. Therefore, the focal length of the lens should be greater than the distance of the object from the lens.

QUESTION: 17

An object is placed before a convex lens. The image formed

Solution:
QUESTION: 18

An object is placed before a concave lens. The image formed

Solution:

Because concave  lens always produce an
Image which is always erect, diminished and virtual.

QUESTION: 19

A lens has a power of +0.5 D. It is

Solution: P=1/f f=1/p. f=1/0.5 f = 2m
QUESTION: 20

A parallel beam of light falling on the eye gets focused on the retina because of refractions at

Solution:

Most of the refraction for the light rays entering the eye occurs at the outer surface of the cornea.

QUESTION: 21

The combination responsible for admitting different amounts of light into the eye is

Solution:
QUESTION: 22

The muscles of the iris control the

Solution:
QUESTION: 23

When the eye is focused on an object very far away, the focal length of the eye-lens is

Solution:
QUESTION: 24

Other names for myopia are

Solution:
QUESTION: 25

The inability among the elderly to see nearby objects clearly because of the weakening of the ciliary muscles is called

Solution:

The inability among the elderly to see near objects clearly because of the weakening of the ciliary muscles is called presbyopia. The focusing power of the eye lens decreases with age.