- Choose the correct option.
(a). The ________ of a mirror is the center of the sphere of which the mirror is a part.
(i) center of curvature (ii)radius of curvature (iii)pole (iv)principal axis.
Answer. (i) center of curvature
(b)Which of the following does not use a concave mirror?
(i)Shaving mirror (ii) Torchlight (iii) Car headlight (iv) Rear-view mirror.
Answer. (iv) Rear-view mirror
(c) A ______ always forms a virtual image.
(i) plane mirror (ii)concave lens (iii)concave mirror (iv)convex lens.
Answer. (i) plane mirror
(d)Light reflects more from:
(i) smooth and polished surfaces (ii)rough surfaces (iii) rough and unpolished surfaces, and (iv) rough and polished surfaces.
Answer. (i) smooth and polished surfaces
Q2. Assertion -Reasoning questions.
For questions number (i) and (ii) statements are given -one labeled as Assertion (A) and the other labeled as Reason (R). Select the correct answer to these questions from the codes (a),(b),(c), and (d) as given below.
- Both Assertion (A) and Reason are (R) are true and reason ( R) is the correct explanation of the Assertation (A )
- Both Assertion (A) and Reason are (R) are true and reason (R) is not the correct explanation of the Assertation (A)
- Assertion (A) is true, but reason (R) is false
- Assertion (A) is false, but reason (R) is true
- Assertion(A): Silver metal is used to coat one side of mirrors Reason ( R ): Silver metal is used to coat one side of mirrors.
Reason (R) : Silver metal is the best reflector of light.
Answer. (a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of the Assertion (A).
(ii) Assertion: A magnifying lens makes the image of an object look larger.
Reason: A magnifying lens is a concave lens.
Answer. (c) Assertion (A) is true, but Reason (R) is false.
Q3. Answer the following questions in one sentence.
- What is reflection of light?
Answer. Reflection of light is the bouncing back of light rays when they hit a smooth surface like a mirror.
- State two uses of a convex lens.
Answer. A convex lens is used in magnifying glasses and in the lenses of cameras
- What is the dispersion of light?
Answer. Dispersion of light is the splitting of white light into its seven colors when it passes through a prism.
- What is lateral inversion?
Answer. Lateral inversion is the reversal of the left and right sides of an image formed in a plane mirror.
Q4. Answer the following questions in 2-3 sentences.
- Compare the principal focus of convex and concave lenses.
Answer. The principal focus of a convex lens is the point where light rays converge after passing through the lens. For a concave lens, the principal focus is the point where light rays appear to diverge from after passing through the lens.
- Why are concave lenses used in flashlights?
Answer. Concave lenses are used in flashlights to spread out the light rays, making the beam of light wider and allowing the flashlight to illuminate a larger area.
- We can see the reflection of the surroundings on the surface of water in the lake Why?
Answer. We can see reflections on the surface of a lake because water is smooth and can act like a mirror, reflecting light rays from the surroundings into our eyes.
Q5.Answer the following questions in 3-4 sentences.
- How is a real image formed? Give one example of the real image.
Answer. A real image is formed when light rays converge and meet at a specific point after reflecting off a mirror or refracting through a lens. A real image can be seen on a screen. An example of a real image is the image formed on a movie screen when light from a projector lens is focused onto it.
- What is a convex mirror? What is the nature of the image formed by it?
Answer. A convex mirror is a curved mirror with its reflective surface bulging outward. It always forms virtual, upright, and smaller images of objects, which means the images appear behind the mirror and cannot be captured on a screen.