If you are given two lenses convex and concave to read a dictionary which lens would you use

A convex lens of focal length 50 cm.
A concave lens of focal length 50 cm.
A convex lens of focal length 5 cm.
A concave lens of focal length 5 cm.

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Last updated at Oct. 7, 2021 by

(a) A convex lens of focal length 50 cm.

(b) A concave lens of focal length 50 cm.

(d) A concave lens of focal length 5 cm.

Answer

Answer is (c) A convex lens of focal length 5 cm.

Explanation

A concave lens will always give a diminished image.

So, we use a convex lens as it makes an enlarged image

Now, the smaller the focal length, the greater will be the power of the lens.

Hence, a convex lens of focal length 5cm will be preferable.

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Page 2

Last updated at April 26, 2020 by Teachoo

Answer

A concave mirror produces an erect image only when

the object is placed between pole and focus.

Now,

Distance between pole and focus = Focal length

= 15cm

Hence, the object can be placed at a distance of less than 15 cm in front of the mirror.

Range of distance of object = less than 15cm

Now,

The nature of the image formed when object is placed between pole and focus of concave mirror is

Virtual, erect and enlarged

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Text Solution

A convex lens of focal length 50 cmA concave lens of focal length 50 cmA convex lens of focal length 5 cm A concave lens of focal length 5 cm

Answer : C

Solution : A magnified image of an object will be obtained when it is placed between the radius of curvature and focal length of a convex lens. Magnification is also higher for convex lenses having shorter focal length. Therefore, for reading small letters, a convex lens of focal length 5 cm should be used.

Question 6 Which of the following lenses would you prefer to use while reading small letters found in a dictionary?a A convex lens of focal length 50 cmb A concave lens of focal length 50 cmc A convex lens of focal length 5 cmd A concave lens of focal length 5 cm

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