## Topic outline

• ### Light

##### Q1. Fill in the blanks.

i.        An image that cannot be obtained on a screen is called virtual image.

ii.        Image formed by a convex mirror is always virtual and smaller in size.

iii.        An image formed by a plane mirror is always of the same size as that of the object.

iv.        An image which can be obtained on a screen is called a real image.

v.        An image formed by a concave lens cannot be obtained on a screen.

vi.        A virtual image larger than the object can be produced by a concave mirror.

##### Q2. True/False

i.        We can obtain an enlarged and erect image by a convex mirror. False

ii.        A concave lens always form a virtual image. True

iii.        We can obtain a real, enlarged and inverted image by a concave mirror. True

iv.        A real image cannot be obtained on a screen. False

v.        A concave mirror always form a real image. False

vi.        In the mirror the right appears left and the left appears right. True

##### Q3. Which type of mirror can form a real image?

Ans. Concave mirror can form a real image.

##### Q4. Which type of lens forms always a virtual image?

Ans.  Concave lens forms always a virtual image.

##### Q5. Give an example of a curved mirror.

Ans. The most common example of a curved mirror is a spherical mirror.

##### Q6. What are the two types of spherical mirror?

Ans. The two types of spherical mirror are concave and convex mirrors.

##### Q7. What is real image?

Ans. An image which can be obtained on a screen is called a real image.

##### Q8. Write some uses of lenses.

Ans. Lenses are widely used in spectacles, telescopes and microscopes.

##### Q9. What is convex mirror?

Ans. If the reflecting surface is convex, then it is a convex mirror.

##### Q10. What happens when light falls on a polished or a shiny surface?

Ans. When light falls on a polished or a shiny surface light gets reflected.

##### Q11. What makes things visible to us?

Ans. Objects are visible only when light reflected from them reaches our eyes.

##### Q12. What is diverging lens?

Ans. A concave lens diverges (bends outward) the light and is called a diverging lens.

##### Q13. What kind of image is formed by concave lens?

Ans. A concave lens always forms erect, virtual and smaller image than the object.

##### Q14. What is the nature of the image formed by a convex mirror?

Ans. Image formed by a convex mirror is erect, virtual and smaller in size than the object.

##### Q15. What is reflection of light?

Ans. Bouncing back of a light ray after hitting any surface is known as reflection of light.

##### Q16. What is concave mirror?

Ans. If the reflecting surface of a spherical mirror is concave, it is called a concave mirror.

##### Q17. Why we are not able to see the candle flame through a bent pipe?

Ans. We are not able to see the candle flame through a bent pipe because light travels along straight lines.

##### Q18. How can we change the path of light?

Ans. We can change the path of light by keeping any shiny or polished or reflecting material in front of the light beam.

##### Q19. What type of image does the outer side of a spoon show?

Ans. The outer surface of a spoon acts like a convex mirror. Image formed by a convex mirror is erect, virtual and smaller in size than the object.

##### Q20. What happens when light falls on a mirror?

Ans. A mirror changes the direction of light that falls on it. This change of direction by a mirror is called reflection of light.