PART - 3 CH - 9 Light-Reflection and Eefraction Science - PART - 3 CH - 9 Light-Reflection and Eefraction

No matter how far you stand from a mirror, your image appears always erect. The mirror is likely to be…

If a spherical mirror is immersed in water, then its focal length…

A boy is running with speed v towards a plane mirror, then at what speed, his image will be running towards him?

From which of the following letters, can we obtain its laterally inverted image?

From which of the following letters, we cannot obtain its laterally inverted image?

________ mirror is used in the head-light of a car.  (Concave, Convex, Plane)

________ is the instrument used to measure the power of a lens. (Dioptre meter, Barometer, Thermometer)

If the power of the correcting lens used in spectacles is - 0.4 D. then the type of lens must be ________ . (Concave, Convex, Cylindrical)

A ________ is used as a magnifying glass. (Convex lens, Concave lens, Plane mirror)

The twinkling of a star is due to atmospheric refraction of starlight.

The absolute refractive index of any medium is greater than 1.

A paper is burned due to the use of a lens by a student.
(1) State the type of lens used by the student.
(2) State the position of the image formed in this phenomenon.
(3) Draw the ray diagram in this phenomenon.

What is reflection of light? Give the types of reflection.

A doctor has prescribed a corrective lens of power + 1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging?

Out of three convex lenses having focal length 10 cm. 20 cm and 30 cm, which lens has maximum power?

Name the type of mirror used in side/rear view mirror of a vehicle.

What is refraction of light? ###Define refraction of light.

Solve the following examples
(1) A convex mirror used for rear-view on an automobile has a radius of curvature of 3.00 m. If a bus is located at 5.00 m from this mirror, find the position, nature and size of the image.

An object, 4.0 cm in size, is placed at 25.0 cm in front of a concave mirror of focal length 15.0 cm. At what distance from the mirror should a screen be placed in order to obtain a sharp image? Find the nature and the size of the image.

Why do we prefer a convex as a rear-view mirror in vehicles?

(i) If the magnification of a lens is +0.35, what will be the nature of the lens? Convex or concave? If the focal length of the Iens is 15 cm, draw a ray diagram in this case to study its image.
(ii) Rakesh projects a beam of light from different angles on a lens placed perpendicular to the table. The beams of light passing through this lens turn at different angles but a ray of light from one place on the lens does not turn even after passing through the lens. Where is this beam of light being projected from? Draw a ray diagram.

Name the type of mirror used in the following situations -
a) Headlights of a car
b) Side/rear-view mirror of a vehicle
c) Solar Furnace

Write a note on the power of a lens.### Write the definition of the power of a lens. State its SI unit. Name the instrument used to measure the power of a lens.

Explain the following terms for a convex lens:
(1) Centre of curvature
(2) Principal axis
(3) Optical centre
(4) Aperture
(5) Radius of curvature
(6) Principal focus
(7) Focal length

A glass slab made of a material of refractive index n₁is kept in a medium of refractive index n₂. A light ray is incident on the slak Draw the path of ray of light emerging from the glass slab. If
(a)n₁>n₂ (b) n₁= n₂(c) n₁ < n₂

What is lateral displacement? Show that a ray incident obliquely on a rectangular glass slab, emerges parallel to the incident ray

Write the uses of concave mirrors

Draw neat ray diagrams and describe the position, nature and size of the image formed by a concave mirror of small aperture for the following positions of the object placed in front of it:
(1) At infinity
(2) At a finite distance beyond C
(3) At C
(4) Between C and F
(5) At F
(6) Between P and F

State the sign convention for lenses.

With neat and labelled ray diagrams, describe the position, nature and relative size of the image formed when an extended object AB is placed at the following positions in front of a convex lens:
(1) At infinite distance
(2) Beyond 2F₁
(3) At 2F₁
(4) Between F₁ and 2F₁
(5) At the principal focus F₁
(6) Between principal focus F₁ and optical centre O

Explain the term absolute refractive index.