Light is a form of energy that travels in the form of waves. It behaves in two main ways when it interacts with surfaces: reflection and refraction.
Reflection of Light:
- Reflection is the bouncing back of light from a surface.
- Law of Reflection: Angle of incidence = Angle of reflection.
- Example: Mirror reflects light to form an image.
Refraction of Light:
- Refraction is the bending of light when it passes from one medium to another.
- The amount of bending depends on the refractive index.
- Example: A straw looks bent in water due to refraction.
Key Differences Between Reflection and Refraction:
- Reflection: Light bounces off a surface.
- Refraction: Light bends when passing through different media.
Practice Questions PDF
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Questions on Light – Reflection and Refraction
Showing 91–120 of 12691.A ray of light is incident at an angle of 30° on a glass slab of refractive index 1.5. Calculate the angle of refraction. (sin 30° = 0.5) 92.A student performs an experiment with a convex lens and determines its focal length to be 10 cm. If an object is placed 8 cm from the lens, describe the characteristics of the image formed. 93.Assertion (A): The bottom of a tank filled with water appears raised. Reason (R): Light rays bend away from the normal when they travel from a denser medium to a rarer medium. 94.A person wishes to see a magnified image of an object using a spherical mirror. What type of mirror should they choose, and where should the object be placed? 95.Explain why a spoon appears bent when partially immersed in water. 96.Compare and contrast the image formation by a concave lens and a convex mirror when the object is placed at infinity. 97.Light enters from air into glass having refractive index 1.50. What is the speed of light in the glass? (Speed of light in vacuum is 3 x 10⁸ m/s). 98.A diverging lens is placed 15 cm from an object. If the image is formed 10 cm from the lens on the same side as the object, calculate the focal length and power of the lens. 99.An object of height 4 cm is placed 20 cm in front of a convex lens of focal length 12 cm. Find the position, nature, and height of the image. 100.The refractive index of diamond is 2.42. What is the meaning of this statement in relation to the speed of light? 101.A ray of light traveling in air enters obliquely into water. Does the light ray bend towards the normal or away from the normal? Explain your answer. 102.Assertion (A): A convex mirror is used as a rear-view mirror in vehicles. Reason (R): A convex mirror forms virtual, erect, and diminished images, and has a wider field of view. 103.Why does a concave mirror form a real image when an object is placed beyond its focal point (F), but a virtual image when the object is placed between the pole (P) and F? 104.New question for #2: An object is placed at 25 cm from a concave mirror of focal length 15 cm. What is the nature and magnification of the image formed? 105.Let's try a simpler one that leads to one of the options. A concave mirror has a focal length of 15 cm. At what distance should an object be placed from it so that it forms a real image at a distance of 30 cm from the mirror? 106.A concave mirror forms a real image of an object magnified 3 times. If the object is moved 10 cm towards the mirror, the image formed is still real and magnified 5 times. Calculate the focal length of the mirror. 107.A boy is standing 10 m in front of a plane mirror. If he walks 2 m towards the mirror, what is the new distance between the boy and his image? 108.We wish to obtain an erect image of an object, using a concave mirror of focal length 15 cm. What should be the range of distance of the object from the mirror? What is the nature of the image? Is the image larger or smaller than the object? 109.Which of the following lenses would you prefer to use while reading small letters found in a dictionary? (a) A convex lens of focal length 50 cm. (b) A concave lens of focal length 50 cm. (c) A convex lens of focal length 5 cm. (d) A concave lens of focal length 5 cm. 110.No matter how far you stand from a mirror, your image appears erect. The mirror is likely to be (a) only plane. (b) only concave. (c) only convex. (d) either plane or convex. 111.Where should an object be placed in front of a convex lens to get a real image of the size of the object? (a) At the principal focus of the lens (b) At twice the focal length (c) At infinity (d) Between the optical centre of the lens and its principal focus. 112.The image formed by a concave mirror is observed to be virtual, erect and larger than the object. Where should be the position of the object? (a) Between the principal focus and the centre of curvature (b) At the centre of curvature (c) Beyond the centre of curvature (d) Between the pole of the mirror and its principal focus. 113.Which one of the following materials cannot be used to make a lens? (a) Water (b) Glass (c) Plastic (d) Clay 114.Find the power of a concave lens of focal length 2 m. 115.A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed in front of the convex lens if the image is equal to the size of the object? Also, find the power of the lens. 116.Define 1 dioptre of power of a lens. 117.The refractive index of diamond is 2.42. What is the meaning of this statement? 118.You are given kerosene, turpentine and water. In which of these does the light travel fastest? 119.Light enters from air into glass which has a refractive index of 1.50. If the speed of light in vacuum is 3 × 10⁸ meters per second, what is the speed of light in the glass? 120.A ray of light travelling in air enters obliquely into water. Does the light ray bend towards the normal or away from the normal? Why?