Physics, asked by mallikakhm8885, 9 months ago

A concave lens has focal length of 20cm. At what distance from the lens a 5cm tall object be placed so early hat it forms an image at 15cm the images formed? ​

Answers

Answered by anandubala0837
1

Answer:

f=-20cm

v=-15

1 over v minus 1 over u equals 1 over f

fraction numerator begin display style 1 end style over denominator begin display style negative 15 end style end fraction minus fraction numerator begin display style 1 end style over denominator begin display style u end style end fraction equals fraction numerator begin display style 1 end style over denominator begin display style negative 20 end style end fraction

fraction numerator begin display style 1 end style over denominator begin display style u end style end fraction equals fraction numerator begin display style 1 end style over denominator begin display style 20 end style end fraction minus fraction numerator begin display style 1 end style over denominator begin display style 15 end style end fraction

fraction numerator begin display style 1 end style over denominator begin display style u end style end fraction equals fraction numerator begin display style 3 minus 4 end style over denominator begin display style 60 end style end fraction

fraction numerator begin display style 1 end style over denominator begin display style u end style end fraction equals fraction numerator begin display style negative 1 end style over denominator begin display style 60 end style end fraction

u equals negative 60

m equals v over u equals fraction numerator H e i g h t space o f space i m a g e left parenthesis h subscript i right parenthesis over denominator H e i g h t space o f space o b j e c t left parenthesis h subscript o right parenthesis end fraction

fraction numerator negative 15 over denominator negative 60 end fraction equals h subscript i over 5

h subscript i equals 5 over 4 equals 1.25 c m.

was that help ful

Answered by Kannan0017
4

1/f = 1/v-1/u

1/(-20) - 1/-15= - 1/u

(15-20)/300 = - 1/u

1/u = - 5/300

u = - 60 cm

hi/ho= v/u

hi/5 = -15/-60

hi=5/4 cm

=1.25 cm ☑️☑️

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