Light: Class 7 Science Q&A · Page 2
35 free answers on Light (Science) for Class 7 students, across CBSE, ICSE and State boards.
Question & Answer
Questions
- ScienceClass 7CBSE
Which of the following can be used to form a real image? (a) Concave mirror only. (b) Plane mirror only. (c) Convex mirror only. (d) Both concave and convex mirrors Soln: (a) concave mirror only
Soln: (a) concave mirror only Explanation: A concave mirror alone can produce a real image. Plane mirror & convex mirror form a virtual image of an object at all times.
- ScienceClass 7CBSE
Boojho and Paheli were given one mirror each by their teacher. Boojho found his image to be erect and of the same size, whereas Paheli found her image erect and smaller in size. This means that the mirrors of Boojho and Paheli are, respectively (a) plane mirror and concave mirror. (b) concave mirror and convex mirror. (c) plane mirror and convex mirror. (d) convex mirror and plane mirror.
Soln: The answer is (c) plane mirror and convex mirror. Explanation: The plane mirror always forms an image of the same size and erected image. Convex mirror forms erected and smaller image.
- ScienceClass 7CBSE
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 (i) 1 m/s (ii) 2 m/s (iii) 4 m/s (iv) 8 m/s
Solution: The correct answer is option (iii) 4 m/s.
- ScienceClass 7CBSE
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 (i) 3 m (ii) 5 m (iii) 6 m (iv) 8 m
Solution: The answer is option (iii) 6 m
- ScienceClass 7CBSE
A virtual image larger than the object can be produced by a (i) concave lens (ii) concave mirror (iii) convex mirror (iv) plane mirror
Solution: The correct answer is option (ii) concave mirror.
- ScienceClass 7CBSE
Which type of lens always forms a virtual image?
Solution: A concave lens forms a virtual image. Choose the correct option in questions 11–13.
- ScienceClass 7CBSE
Which type of mirror can form a real image?
Solution: The concave mirror can form a real image.
- ScienceClass 7CBSE
Give one use each of a concave and a convex mirror.
Solution: Concave mirrors are used in the headlights of cars and scooters. Convex mirrors are used as side-view mirrors in vehicles.
- ScienceClass 7CBSE
State two differences between a convex and a concave lens.
Solution: Convex Lens Concave Lens Thick in the middle and thin at the edge. Thin in the middle and thick at the edge. The image formed is real or virtual. The image formed is virtual.
- ScienceClass 7CBSE
What is a virtual image? Give one situation where a virtual image is formed.
Solution: The image that cannot be obtained on a screen is called a virtual image. The image formed by a plane mirror is virtual.
- ScienceClass 7CBSE
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.
Solution: A, H, I, M, O, T, U, V, W, X, and Y alphabets form images in a plane mirror exactly like the letter itself because these alphabets are laterally symmetric.
- ScienceClass 7CBSE
State the characteristics of the image formed by a plane mirror.
Solution: Characteristics of the image formed by a plane mirror are as follows: Image distance and object distance are equal. The size of the object and image are equal. The image formed is erect and virtual. Images are laterally inverted.
- ScienceClass 7CBSE
Match the items given in Column I with one or more items in Column II. Column-I Column-II (a) A plane mirror (i) Used as a magnifying glass. (b) A convex mirror (ii) Can form images of objects spread over a large area. (c) A convex lens (iii) Used by dentists to see an enlarged image of teeth. (d) A concave mirror (iv) The image is always inverted and magnified. (e) A concave lens (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.
Solution: Column-I Column-II (a) A plane mirror (v) The image is erect and of the same size as the object. (b) A convex mirror (ii) Can form an image of objects spread over a large area.
- ScienceClass 7CBSE
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 form 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)
Solution: a) False b) True c) True d) False e) False
- ScienceClass 7CBSE
Fill in the blanks. (a) An image that cannot be obtained on a screen is called a ____________. (b) Image formed by a convex __________ is always virtual and smaller in size. (c) An image formed by a __________ mirror is always of the same size as that of the object. (d) An image which can be obtained on a screen is called a _________ image. (e) An image formed by a concave ___________ cannot be obtained on a screen.
Solution: (a) An image that cannot be obtained on a screen is called a virtual image. (b) Image formed by a convex mirror is always virtual and smaller in size. (c) An image formed by a plane mirror is always of the same size as that of the object. (d) An image which can be obtained on a screen is called a real image. (e) An im