Physics, asked by Sunidhi248, 11 months ago

a person suffering from long sightedness can see at most 12.5 cm. which lens and what focal length should be used for clear vision? the least distance for clear vision is 25 cm.

Answers

Answered by sujay60

Concave lens can be used to clear the focal length and clear vision for 20cm

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Sunidhi248: can you plz send me the soluiton pic

sujay60: one second

Sunidhi248: sry to say bt accordong to my text book the correct ans is 13.25cm, and convex len it correct ans

sujay60: how r u sending pics

Sunidhi248: you can send pics by click on answering my question

sujay60: tq sister

Sunidhi248: oh god o m totally confused now

Answered by shashiawasthi069

Explanation:

u = -25 cm

v = -12.5cm

f = ?

using lens formula

1/f = 1/v -1/u

1/f = 1/(-12.5) - 1/(-25)

1/f = 1×10/(-12.5)×10 - 1/(-25)

1/f = 10/(-125) - 1/(-25)

1/f = -2/25 + 1/25

1/f = (-2+1)/25

1/f = -1/25

f = -25cm

focal length is negative it means concave lens with focal length 25 cm

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