Students can Download Science Chapter 15 Light Questions and Answers, Notes Pdf, KSEEB Solutions for Class 7 Science helps you to revise the complete Karnataka State Board Syllabus and to clear all their doubts, score well in final exams.
Karnataka State Syllabus Class 7 Science Chapter 15 Light
Class 7 Science Light Textbook Exercise Questions and Answers
Question 1.
Fill in the blanks:
- An image that cannot be obtained on a screen is called ______________.
- The image formed by a convex: ______________ is always virtual and smaller in size.
- An image formed by a ______________ mirror is always of the same size as that of the object.
- An image that can be obtained on a screen is called an ______________ image.
- An image formed by a concave ______________ cannot be obtained on a screen.
Answer:
- virtual image
- mirror
- plane
- real
- lens
Question 2.
Mark ‘T’ if the statement is true and ‘F’ if it is false:
(a) We can obtain an enlarged and erect image by a convex mirror. (T/F)
(b) A concave lens always forms a virtual image. (T/F)
(c) We can obtain a real, enlarged, and inverted image by a concave mirror. (T/F)
(d) A real image cannot be obtained on a screen. (T/F)
(e) A concave mirror always forms a real image. (T/F)
Answer:
(a) False
(b) True
(c) True
(d) False
(e) False
Question 3.
Match the items given in Column I with one or more items of column II.
| Column I | Column II |
| (a) A plane mirror (b) A convex mirror (c) A convex lens (d) A concave mirror (e) A concave, lens |
(i) Used as a magnifying glass. (ii) It can form the image of objects spread over a large area. (iii) Used by dentists to see an enlarged image of teeth. (iv) The image is always inverted and magnified. (v) The image is erect and of the same size as the object. (vi) The image is erect and smaller in size than the object. |
Answer:
(a) (v),
(b) (ii) and (vi)
(c) (i) (d) (iii)
(e) (vi)
Question 4.
State the characteristics of the image formed by a plane mirror.
Answer:
- The image formed by a plane minor is erect and virtual.
- The image is of the same size as that of the object.
- The distance of the image from the mirror is the same as the distance between the mirror and object.
Question 5.
Find out the letters of the English alphabet or any other language known to you in which the image formed in a plane mirror appears exactly like the letter itself. Discuss your findings.
Answer:
The letters of the English alphabet A, H, 1, M, O, T, U, V, W, X, Y would form images that exactly look like the original letters when kept in front of a plane mirror. These letters have a vertical line of symmetry. Hence, if we divide them in the middle, we would find that the right halves are equivalent to the left halves of the letters.
Question 6.
What is the virtual image? Give one situation where a virtual image is formed.
Answer:
The image, which cannot be obtained on a screen is called a virtual image. The images formed by a plane mirror, convex mirror, and concave lens are virtual.
Question 7.
State two differences between a convex and a concave lens.
Answer:
| Convex lens | Concave lens |
| (a) It is thicker in the middle than the edges. (b) It converges the light rays falling on it. |
(a) It is thinner in the middle than the edges. (b) It diverges the light rays falling on it. |
Question 8.
Give one use each of a concave and a convex mirror.
Answer:
Concave mirror: It is used by dentists to see an enlarged image of the teeth.
Convex mirror: It is used as a side-view mirror of the car because it enables the drivers to view objects spread over a large area behind them.
Question 9.
Which type of mirror can form a real image?
Answer:
A concave mirror can form a real image.
Question 10.
Which type of lens forms always a virtual image?
Answer:
A concave lens always forms a virtual image.
Choose the Correct Option in Questions:
Question 11.
A virtual image larger than the object can be produced by a :
(a) concave lens
(b) concave mirror
(c) convex mirror
(d) plane mirror
Answer:
(b) concave mirror.
Question 12.
David is observing his image in a plane mirror. The distance between the mirror and his image is 4 m. If he moves 1 m towards the mirror, then the distance between David and his image will be:
(a) 3 m
(b) 5 m
(c) 6 m
(d) 8 m
Answer:
(c) 6 m
Question 13.
The rearview mirror of a car is a plane mirror. A driver is reversing his car at a speed of 2 m/s. The driver sees in his rearview mirror the image of a truck parked behind his car. The speed at which the image of the truck appears to approach the driver will be:
(a) 1 m/s
(b) 2 m/s
(c) 4 m/s
(d) 8 m/s
Answer:
(c) 4 m/s