CBSE Class 7 Science Light Worksheet

ACTIVITY-15.2: Reflection through a mirror.

Q1 If a ray of light makes an angle of 300 with the plane mirror, what will be the angle of reflection?

Q2 If a ray of light falls normally on a plane mirror how will it be reflected back? What will be the angle of incidence and angle of reflection?

Q3 How is word AMBULANCE written in front of ambulance van and why? 

Q4 Why is the image formed in plane mirror said to be virtual?

Q5 If a person is standing in front of plane mirror at a distance of 5m and he steps 2.5m forwards ,what will be the distance between him and his image?

Q6 Which type of mirror can form a real image?

Q7 Which mirror is used by dentists and why?

Q8 which mirror can produce virtual image larger than the object?

Q9 Why is concave mirror preferably used by makeup artists?

Q10 Which lens is used as a magnifying glass and why?

Q11 Which type of lens always forms a virtual image?

Q12 Why on rear view mirrors in vehicles it is generally written---“objects are closer than they appear”?

Q13 Why does a colored disc appear white when rotated ?

Q14 Give any four examples of real image.

Q15 A person stands in front of a specially designed mirror in which upper part of his body appears to be erect and magnified, middle part erect and smaller and lower part erect and same size. Explain the design of the mirror.

1.Does light travels in straight line?

2.Can a shiny surface change the direction of the light?

3.Does light get reflected from a plane mirror?

4.What is a real image?

5.What is a virtual image?

6.What is a concave lens?

7.What is a convex lens?

8.Can we obtain an image on screen by a plane mirror?

9.Which type of lens always forms a virtual image?

10.Another candle appears behind the mirror when we place a candle in front of it.
(A) The candle behind the mirror is known as the image.
(B) The candle in front of the mirror is called the object.
(C) Both (1) and (2).
(D) None of the above.

11.Convex mirror has its reflecting (shining) surface-
(A) Similar to the inner surface of a spoon.
(B) Bulging in.
(C) Both (a) and (b).
(D) Neither (a) nor (b).

12.An image formed by a plane mirror, that cannot be obtained on a screen is called a-
(A) Real Image.
(B) Virtual Image.
(C) Erect Image.
(D) Inverted image.

13.By using a concave mirror, we can see an image that is-
(A) Real or virtual.
(B) Smaller or larger than the object.
(C) Inverted or erect.
(D) All of these.

14.By using a convex mirror, we can see an image that is-
(A) Real, inverted and enlarged.
(B) Virtual, erect and diminished.
(C) Real, erect and diminished.
(D) Virtual, erect and enlarged.

15.Those lenses which are thicker in the middle than at the edges are-
(A) Concave lenses.
(B) Diverging lenses.
(C) Magnifying lenses.

(D) Magnifying glasses or convex lenses.
16.The nature and size of an image depend upon-
(A) The time of conducting the experiment.
(B) The position of the object.
(C) The kind of the object.
(D) The position of the object in case of mirrors only.

17.Concave lenses are also known as-
(A) Diverging lenses because they diverge light.
(B) Converging lenses because they converge light to a point.
(C) Diverging lenses because they bend the light outward.
(D) Only (a) and (c).

18.Sunlight consists of-
(A) White colour only.
(B) Five colours.
(C) Seven colours.
(D) Blue colour.

19.The correct sequence of seven colours of a rainbow is-
(A) Blue, Orange, Red, White, Purple, Yellow, Green.
(B) Violet, Blue, Indigo, Green, Red, Yellow, Orange.
(C) Red, Orange, Yellow, Green, Blue, Indigo, Violet.
(D) Red, Orange, Yellow, Green, Violet, Indigo, Blue.

20.Concave mirror has its reflecting (shining) surface-
(A) Bulging in.
(B) Bulging out.
(C) Like the outer surface of a spoon.
(D) Both (b) and (c).

21.The image can be obtained on a screen, if-
(A) The screen is placed behind the plane mirror.
(B) The screen is placed in front of the plane mirror.
(C) The screen is placed in front or behind the plane mirror.
(D) The image cannot be obtained on a screen using a plane mirror.

22.In an image obtained by a plane mirror, left side of the object appears to be-
(A) Theleft side of the image.
(B) Theright side of the image.
(C) Thetop of the image.
(D) Thebottom of the image.

23.In the side mirror of a car, the images of all the objects appear-
(A) Equal to the objects.
(B) Smaller than the objects.
(C) Larger than the objects.
(D) As points.

24.The shape of a mirror can be-
(A) Plane.
(B) Convex.
(C) Concave.
(D) All the three.

25.The distance of the image from a plane mirror is-
(A) More than the distance of the object from the mirror.
(B) Less than the distance of the object from the mirror.
(C) Same as the distance of the object from the mirror.
(D) None of these.

26.If a small circular disc with seven rainbow colours painted on it, is rotated, we see-
(A) The seven colours rotating in the same sequence.
(B) The seven colours become brighter.
(C) Black colour.
(D) White colour.

27.The image formed by a plane mirror is-
(A) Of smaller size, if the mirror is larger.
(B) Of smaller size, if the mirror is smaller.
(C) Of the same size as that of the object - does not matter if the mirror is small or large.
(D) Of larger size, if the mirror is larger.

28.Objects become visible to us because-
(A) Light is absorbed by them.
(B) Light is reflected by them before reaching our eyes.
(C) They obstruct the path of light.
(D) None of these.

29.Direction of reflected light changes if-
(A) The mirror is rotated slightly.
(B) The object is moved sideways.
(C) Both (1) and (2).
(D) None of these.

30.You cannot see the flame of a lighted candle through a bent pipe, but you can see it through a straight pipe, because:
(A) Light travels in a straight line.
(B) Pipe is polished.
(C) Bent pipe was blocked.
(D) All of these.

31.When light falls on a polished or shiny surface-
(A) The light is absorbed by it.
(B) The direction of light changes.
(C) The light gets deflected in different directions.
(D) All of these.

32.The change in direction of light after striking a mirror is called-
(A) Beam of light.
(B) Searchlight.
(C) Reflection of light.
(D) Path of light.

33.Those transparent glasses which are thinner in the middle than at the edges are-
(A) Concave lenses
B) Magnifying glasses.
C) Used in microscopes.
D) Used in telescopes.

34.The image formed by a plane mirror will be-
(A) Larger.
B) Erect.
(C) Inverted.
(D) Tilted.

35.Which of the following mirror is used by the doctors?
(A) Convex.
(B) Plane.
(C) Concave.
(D) Both concave and convex.

36.Reflector of a torch has-
(A) Plain surface.
(B) Concave surface.
(C) Convex surface.
(D) Irregular surface.

37.Can you identify lenses just by touching?
(A) No.
(B) Yes.
(C) Only convex lenses.
(D) Only concave lenses.

38.A circular disc with all the seven colours of rainbow painted on it in correct sequence, is called-
(A) Circular disc.
(B) Rainbow disc.
(C) VIBGYOR disc.
(D) Newton's disc.

39.We can see a rainbow only when-
(A) Our face is towards the Sun.
(B) Our back is towards the Sun.
(C) We look at the Sun.
(D) We look anywhere in the sky.

40.What do you mean by reflection of light?

41.How are objects visible?

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42.Explain why we can't see the flame of a candle through a bent pipe?

43.How do we know that ambulance is coming behind our vehicles?

44.How can we see the image formed by a lens?

45.What are the characteristics of the image formed by a concave lens?

46.What are the characteristics of the image formed by a convex mirror?

47.What are the characteristics of the image formed by a plane mirror?

48.Which lens is used as magnifying glass? Why?

49.How are convex mirrors used?

50.List various uses of lenses?

<3M>

51.Explain an activity in which images are interchanged sideways.(lateral version)

52.Differentiate between concave lens and convex lens.

53.State the characteristics of the image formed by a concave mirror when the object is placed very close.

54.Which mirrors are used as side mirrors in scooters and cars? Justify your answer.

55.What are the uses of concave mirrors?

56.What are concave mirrors and convex mirrors?

<5M>

57.Differentiate between real and virtual image.

58.Explain Newton's disc.

Q.1 Fill in the blanks:-

(i) Light always travels in a ____________.

(ii) Change in direction of light after striking a polished surface is called ____________.

(iii) The phenomenon of left appearing right and right appearing left on reflection from a mirror is called _____________.

(iv) Real images are always ____________ while virtual images are always __________. (erect/inverted)

(v) The reflecting side of a concave mirror curves ____________ while the reflecting side of a convex mirror curves ______________ (inwards/outwards)

(vi) Concave mirrors from ____________ and ____________ images whereas the image formed by a convex mirror is always ____________ (real/virtual)

(vii) ____________ mirrors are used as rear/side view mirrors and ____________ mirrors are used as reflectors of headlights of vehicles.

(viii) A ____________ lens converges rays of light falling on it hence it is also called a ____________ lens.

(ix) A concave lens always forms a ____________ (real/virtual) image which is ____________ (erect/inverted) and ____________ (smaller/bigger) than the object.

(x) Formation of shadows suggest that light travels in __________ lines.

(xi) A __________ lens is thicker in the middle and tapering at the edges.

Q.2 Multiple choice questions (Choose the correct option)

(A) A virtual image formed by a plain or a spherical mirror
(a) is always inverted
(b) is always erect
(c) is erect or inverted depending on the distance of the object from the mirror

(B) which of the following images can a convex lens not produce?
(a) Real, Magnified
(b) Virtual, magnified
(c) erect, virtual
(d) erect, diminished

(C) which of the following is true for a convex mirror?
(a) It can only form virtual images
(b) It can only form real images
(c) It can form real or virtual images depending on the distance of the object from the mirror
(d) It can form real or virtual images depending on the size of the object.

(D) which of the following can not split light into its seven colours?
(a) diamond cut in a special way
(b) Prism
(c) Convex Lens
(d) Water droplets suspended in the air.

(E) Sodium chloride will turn
(a) Blue Litmus Red
(b) Methyl orange yellow
(c) Red Litmus blue
(d) None of these

1. How does a plane mirror differ from a spherical mirror?

2. State the law of reflection.

3. How many reflected rays can be for a given incident ray falling on a plane mirror?

4. Two plane mirrors are placed 900 to each other. An incident ray AB falls on one of the mirrors at 450. Draw the path of the reflected ray.

5. Write down five English alphabets which do not show lateral inversion on reflection from a plane mirror.

6. You are standing at a distance of 1m. from a plane mirror (a) What is the distance between you and your image (b) By how much distance does your image move from you if you had walked 2m away from the original position.

7. Under what conditions should a concave mirror, a plane mirror, a convex mirror form virtual images?

8. (a) What type of mirror is used in the following and why?
(1) In a search light (2) as a side view mirror in a car (C) as a shaving mirror (4) vigilance mirror in a big shop.
(b) Why is light not visible through a bent pipe?
(c) If we want to make fire with the help of a lens using the rays of the Sun, what kind of lens should be used and why?
(d) What kind of mirrors do the two surfaces of a spoon act as?

HOTS QUESTIONS

Q.1 What will be the difference in the size of the image (of the same object) formed by a small and a large plane mirror?

Q.2 Identity three letters of the English alphabet or of your mother tongue whose mirror 3.

Q.3 Car rear view mirrors carry a warning message that ‘objects in the rear view mirror are closer than they appear’. Why do you think this is so?

Q.4 How many images do you think will be formed if an object is kept between two plane mirrors parallel to each other?

I. Fill in the blanks :

1. The change in the direction of light by a mirror is called ______________.

2. The image formed by a ____________ lens is always virtual, erect and smaller in size.

3. White light is composed of ______________ colours.

4. The image of an object formed by a _____________ cannot be obtained on a screen.

5. _____________ are used by dentists to see an enlarged image of the teeth.

II Name the following :

1. An image that can be obtained on the screen -

2. The lens which feel thinner in the middle than at the edges -

3. The lens known as magnifying glass -

4. The lens known as diverging lens -

5. The mirror which can form both real as well as virtual images.

6. The large arc of seven colours VIBGYOR in the sky.

III State whether True or False :

1. The image formed by a plane mirror is inverted -

2. A convex lens is thicker in the middle than at the edges -

3. A concave mirror always forms real image -

4. Any polished or shining surface can act as mirror -

IV Define :

Reflection of light

V Distinguish:

Real image & Virtual image

L-15 LIGHT

I. DEFINE THE FOLLOWING:

Question 1. Rectilinear propagation of light
Answer: The property of light traveling in a straight line in a transparent medium is called rectilinear propagation of light.
In simple words: Light always travels in straight lines.

Exam Tip: Mention the straight-line path of light to secure full marks.

Question 2. Reflection of light
Answer: The bouncing back of light rays when they strike a polished, shiny surface like a mirror is called reflection of light.
In simple words: Light bounces off shiny surfaces like a ball hitting a wall.

Exam Tip: Key terms include 'bouncing back' and 'polished surface'.

Question 3. Lateral inversion
Answer: The phenomenon in which the right side of an object appears as the left side and the left side appears as the right side in a mirror image is called lateral inversion.
In simple words: Left becomes right and right becomes left in a mirror.

Exam Tip: Use an example like lifting your right hand to explain lateral inversion clearly.

Question 4. Dispersion of light
Answer: The splitting of white light into its seven constituent colors (VIBGYOR) when passing through a transparent medium like a glass prism is called dispersion of light.
In simple words: White light splits into seven colors.

Question 1. Real and virtual image
Answer:

In simple words: Real images can be caught on a screen and are upside down, while virtual images cannot be caught on a screen and are upright.

Exam Tip: Always present differences in a tabular format for better clarity.

Question 2. Convex mirror and concave mirror
Answer:

In simple words: Convex mirrors bulge out and make images smaller, while concave mirrors curve inward and can make images larger.

Exam Tip: Focus on the shape of the reflecting surface and the nature of the images formed.

Question 3. Convex lens and Concave lens
Answer:

In simple words: Convex lenses are thick in the middle and bring light rays together, whereas concave lenses are thin in the middle and spread light rays apart.

Exam Tip: Note that convex lens converges light, whereas concave mirror also converges light—do not confuse lenses and mirrors.

Question 4. Mirror and lens
Answer:

In simple words: Mirrors reflect light off a polished surface, while lenses refract (bend) light passing through them.

Exam Tip: The core difference is reflection versus refraction.

III. ANSWER THE FOLLOWING:

Question 1. Write the characteristics of the image formed by a plane mirror.
Answer: The characteristics of the image formed by a plane mirror are:
1. It is virtual and erect.
2. It is of the same size as the object.
3. It is formed at the same distance behind the mirror as the object is in front of it.
4. It is laterally inverted (left appears right and right appears left).
In simple words: A plane mirror gives an upright, same-sized, virtual image that is flipped sideways and appears as far behind the mirror as you are in front of it.

Exam Tip: List at least three key characteristics clearly to score full marks.

Question 2. Why the word AMBULANCE is written in a strange manner in front of an ambulance ?
Answer: The word AMBULANCE is written laterally inverted (as \(\text{ECNALUBMA}\)) so that the driver of the vehicle driving ahead in the same direction can read it correctly in their rear-view mirror through lateral inversion and give way immediately.
In simple words: It is written backward so drivers ahead can read it correctly in their rearview mirrors and make way quickly.

Exam Tip: Mention 'lateral inversion' and 'rear-view mirror' as key scientific reasons.

Question 3. Write any three uses of a concave mirror.
Answer: Three uses of a concave mirror are:
1. Used by dentists to see enlarged images of teeth.
2. Used as reflectors in headlights of cars, scooters, and searchlights to get a powerful parallel beam of light.
3. Used as shaving mirrors to see an enlarged image of the face.
In simple words: They are used in torches, dentist tools, and shaving mirrors because they can form magnified images or strong beams of light.

Exam Tip: Give practical everyday examples to show understanding.

Question 4. Name the type of mirror used as side view mirror in vehicles. Why?
Answer: A convex mirror is used as a side-view mirror in vehicles.
Reason: Convex mirrors always form virtual, erect, and highly diminished (smaller) images of objects, thereby providing a much wider field of view of traffic behind the driver.
In simple words: Convex mirrors are used because they let drivers see a wide area of traffic behind them in a small mirror.

Exam Tip: Always state both the mirror type and the reason (wider field of view).

Question 5. Name the type of lens used as magnifying glass. Why?
Answer: A convex lens is used as a magnifying glass.
Reason: When an object is placed close to a convex lens, it forms an erect, virtual, and magnified (enlarged) image of the object.
In simple words: A convex lens makes small objects look larger when held close to them.

Exam Tip: Specify that the object must be placed within the focal length to get a magnified virtual image.

Question 6. Write the characteristics of the image formed by
a) Convex mirror
Answer: Virtual, erect, and diminished (smaller than the object).
b) Concave mirror
Answer: Can form real or virtual images; real images are inverted, virtual images are erect; can be magnified, same size, or diminished depending on the object's position.
c) Convex lens
Answer: Can form real and inverted images (or virtual, erect, and magnified image when the object is very close).
d) Concave lens
Answer: Always forms virtual, erect, and diminished images.
In simple words: Different mirrors and lenses produce different types of images based on their curvature and how they bend light.

Exam Tip: Memorize the nature, size, and position rules for all standard mirror and lens setups.

Question 7. How can you show that white light consist of seven colours?
Answer: Pass a beam of sunlight through a glass prism in a dark room. The white light splits into a band of seven colors (VIBGYOR) on a white screen or wall, demonstrating that white light is composed of seven colors. Alternatively, Newton's color disc experiment can also be used.
In simple words: Shine white light through a prism to see it split into a rainbow of seven colors.

Exam Tip: Mention the glass prism and the resulting VIBGYOR band.

Question 8. We should not look at the sun through a convex lens Why?
Answer: A convex lens converges a large amount of sunlight onto a very small focal point. Looking directly at the sun through it concentrates intense heat and light energy, which can permanently damage the retina of the eyes and cause blindness.
In simple words: It focuses too much burning sunlight into your eyes and can blind you.

Exam Tip: Emphasize the converging nature of the convex lens and its dangerous heating effect on the retina.

Question 9. What are converging and diverging lens?
Answer: 1. Converging lens: A lens that bends (refracts) parallel rays of light inward to a single point (focus). A convex lens is a converging lens.
2. Diverging lens: A lens that spreads out parallel rays of light in different directions. A concave lens is a diverging lens.
In simple words: Converging lenses bring light rays together, while diverging lenses spread them apart.

Exam Tip: Associate convex with converging and concave with diverging.

Question 10. Write any two natural phenomenon taking place due to dispersion of light.
Answer: Two natural phenomena due to dispersion of light are:
1. Formation of a rainbow in the sky after rainfall.
2. Formation of colored patterns (spectrum) on soap bubbles or thin oil films.
In simple words: Rainbows and colored soap bubbles are natural examples of light splitting into colors.

Exam Tip: The formation of a rainbow is the classic and most important example to quote.