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WorksheetsLight-Reflection And Refraction
Total questions: 32
Worksheet time: 16mins
Refractive index What is the first statement of the video clip?
Hi kids, today we will learn about refraction
So let's start, we learnt what is reflection and it's types already
When light exists in a single medium air or water or glass
It moves in a single straight line and at a constant speed until it is obstructed by some object
When it is obstructed by some object it reflects at the angle which is the same as the angle at which it hits the object
The velocity of light in water is 3/4times the velocity of light in vacuum. Find
the refractive index of water.
What is the distance between the image and the plane mirror, if the object is
at 15 m?
How can we find the (rough) focal length of a concave mirror?
. A concave mirror of focal length 1.5m forms an image of an object placed at
a distance of 40cm. Find the position and nature of the image
A person wants to see the full length image of tall building in a small
mirror. Which type of mirror is used by him?
Why do we not see the actual depth of a lake?
The refractive indices of water and glass are and respectively. Write the
relation and find the value of refractive index of water with respect to glass and
glass with respect to water.
A concave mirror and a convex lens are held separately in water. What
changes, if any, do you expect in the focal length of either?
. Redraw the following diagrams given below in your answer book and show
the direction of the light ray after refraction from the lens.
A convergent lens has a focal length of 15 cm. At what distance should an
object from the optical centre of the lens be placed so that its real image is
formed at 30 cm on the other side of the lens?
An object is placed between infinity and the pole of a convex mirror. Draw a
ray diagram and also state the position, the relative size and the nature of the
image formed.
Draw the ray diagram and also state the position, relative size and nature of
the image formed by a concave mirror when the object is placed between its
centre of curvature, C and the focus, F.
Define ‘refractive index of a transparent medium.’ What is its unit? Which
has a higher refractive index, glass or water?
The image of a candle flame placed at a distance of 45 cm from a spherical
lens is formed on a screen placed at a distance of 90 cm from the lens. Identify
the type of lens and calculate its focal length. If the height of the flame is 2 cm,
find the height of its image.
An object 2 cm in size is placed 30cm in front of a concave mirror of focal
length 15cm. At what distance from the mirror should a screen be placed in order
to obtain a sharp image? What will be the nature and the size of the image
formed? Draw a ray diagram to show the formation of the image in this case.
. A convex lens has a focal length of 10 cm. At what distance from the lens
should the object be placed so that it forms a real and inverted image 20 cm away
from the lens? What would be the size of the image formed if the object is 2 cm
high? With the help of a ray diagram show the formation of the image by the lens
in this case.
A concave lens has focal length of 20 cm. At what distance from the lens a
5 cm tall object be placed so that it forms an image at 15 cm from the lens? Also
calculate the size of the image formed.
What is meant by power of a lens? Name and define its S.I. unit.
One student uses a lens of focal length +50 cm and another of –50cm. State the
nature and find the power of each lens. Which of the two lenses will always give a
virtual, erect and diminished image irrespective of the position of the object?
5 cm tall object is placed perpendicular to the principal axis of a convex
lens of focal length 18 cm at a distance of 12 cm from it. Use lens formula to
determine the position, size and nature to the image formed.
What is meant by ‘power of a lens’?
State and define the S.I. unit of power of a lens.
A convex lens of focal length 25 cm and a concave lens of focal length 10
cm are placed in close focal contact with each other. Calculate the lens power of
this combination.
With the help of a ray diagram, state the meaning of refraction of light.
State Snell’s law of refraction of light and also express it mathematically.
. The refractive index of water with respect to vacuum is 4/3and refractive
index of vacuum with respect to glass is 2/3.If the speed the speed of light in glass
is 2 × 108 ms-1
, find the speed of light in (i) vacuum, (ii) wate
With the help of a ray diagram explain why a concave lens diverges the
rays of a parallel beam of light.
A 2.0 cm tall object is place perpendicular to the principal axis of a
concave lens of focal length 15 cm. At what distance from the lens, should the
object be placed so that it forms an image 10 cm from the lens? Also find the
nature and the size of image formed.
Draw the ray diagram in each case to show the position and nature of the
image formed when the object is placed:
Draw the ray diagram in each case to show the position and nature of the
image formed when the object is placed:
Between the pole P and focus F of a concave mirror
Draw the ray diagram in each case to show the position and nature of the
image formed when the object is placed:
In front of a convex mirror
Draw the ray diagram in each case to show the position and nature of the
image formed when the object is placed:
Draw the ray diagram in each case to show the position and nature of the
image formed when the object is placed:
