Page 138 - Ripples SCIENCE 7 - TEJPUR Edition 2024 Answer Key

v A convex lens is also known as converging lens & a concave lens is also known as diverging

lens.
v When the Sun appears just after it has rained, sunlight hits the tiny water droplets & a

rainbow appears. It contains a band of seven colours in the order of VIBGYOR–voilet, indigo,
blue, green, yellow, orange & red.
v Newton's disc, invented by Sir Issac Newton, is a disc with seven segments painted in seven

different colours of the rainbow. When the disc is rotated at a high speed, the colours fade
to white.

v Hans Lippershey, in 1608, was the first to request patent for the device he invented using
lenses that could magnify objects to three times their size, later to be known as the telescope.

Exercise
A. Tick (3) the correct answer.
1. An erect and enlarged image can be formed by ...................... .

(a) A convex mirror (b) A concave mirror
(c) A plane mirror (d) Both (a) and (b)

Ans: (b)
2. Which of the following can be used to form a real image?
(a) Concave mirror (b) Plane mirror

(c) Convex mirror (d) Both concave and convex mirrors
Ans: (a)

3. The image formed by a plane mirror is ...................... .
(a) Left-right inverted (b) Of the same size as that of the object
(c) Erect and virtual (d) All of these

Ans: (d)
4. Which of the following always diverges light rays?
(a) Convex mirror and plane mirror (b) Convex lens and concave mirror

(c) Concave mirror and convex mirror (d) Concave lens and convex mirror
Ans: (d)
5. A virtual image ...................... .

(a) can be formed on the screen (b) cannot be formed on the screen
(c) Is formed only by a plane mirror (d) Is formed only by a convex mirror

Ans: (b)
6. A ray of light parallel to the principle axis passes or appears to pass through the
.................. .

(a) Focus of the mirror (b) Center of curvature of the mirror
(c) Pole (d) None of the above

Ans: (a)

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