1Exercises13 questions
Q.1Fill in the blanks:
(a) An image that cannot be obtained on a screen is called __________.
(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.v
Answer:(a) virtual image
(b) mirror
(c) plane
(d) real
(e) lens
Q.2Mark '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 form a real image. (T/F)v
SolutionA convex mirror forms a virtual, erect and diminished image. A concave lens always forms a virtual image. A concave mirror can form real enlarged inverted images for some object positions, but it can also form virtual images.
Answer:(a) F
(b) T
(c) T
(d) F
(e) F
Q.3Match the items given in Column I with one or more items of Column II:
Column I: A plane mirror, A convex mirror, A convex lens, A concave mirror, A concave lens. Column II: Used as a magnifying glass, Can form image of objects spread over a large area, Used by dentists to see enlarged image of teeth, The image is always inverted and magnified, The image is erect and of the same size as the object, The image is erect and smaller in size than the object.v
Answer:A plane mirror - The image is erect and of the same size as the object. A convex mirror - Can form image of objects spread over a large area; the image is erect and smaller in size than the object. A convex lens - Used as a magnifying glass. A concave mirror - Used by dentists to see enlarged image of teeth. A concave lens - The image is erect and smaller in size than the object.
Q.4State the characteristics of the image formed by a plane mirror.v
Answer:The image formed by a plane mirror is virtual, erect, of the same size as the object, laterally inverted and appears as far behind the mirror as the object is in front of it.
Q.5Find out the letters of 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.v
Answer:Letters with vertical symmetry look the same in a plane mirror. In block capital English letters, examples include A, H, I, M, O, T, U, V, W, X and Y, depending on the font.
Q.6What is a virtual image? Give one situation where a virtual image is formed.v
Answer:A virtual image is an image that cannot be obtained on a screen. A plane mirror forms a virtual image of an object placed in front of it.
Q.7State two differences between a real image and a virtual image.v
Answer:A real image can be obtained on a screen, while a virtual image cannot be obtained on a screen. A real image is usually formed when light rays actually meet, while a virtual image appears to be formed where rays seem to come from.
Q.8Give one use each of a concave and a convex mirror.v
Answer:A concave mirror is used by dentists to see enlarged images of teeth. A convex mirror is used as a rear-view mirror in vehicles because it gives a wider view.
Q.9Which type of mirror can form a real image?v
Answer:A concave mirror can form a real image.
Q.10Which type of lens forms always a virtual image?v
Answer:A concave lens always forms a virtual image.
Q.11A virtual image larger than the object can be produced by a
(i) concave lens (ii) concave mirror (iii) convex mirror (iv) plane mirrorv
- a. concave lens
- b. concave mirror
- c. convex mirror
- d. plane mirror
SolutionA concave mirror can form a virtual, erect and enlarged image when the object is close to the mirror.
Answer:(ii) concave mirror
Q.12David 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 mv
SolutionIn a plane mirror, image distance behind the mirror equals object distance in front. Initially David is 4 m from the mirror. After moving 1 m towards it, he is 3 m from the mirror and his image is 3 m behind it. Distance between David and image = 3 + 3 = 6 m.
Q.13The rear view 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 rear view 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/sv
SolutionFor a plane mirror, the image is as far behind the mirror as the object is in front. If the car mirror moves towards the stationary truck at 2 m/s, the separation between the driver and the image decreases at twice this speed, 4 m/s.