Question

HELLO ✌

⤵⤵Solve the numerical ⤵⤵

A convex lens produces a real and inverted image 2.5 times magnified at a distance of 25 cm from tge lens . calculate focal length of the lens .

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Answer 1

Hey Dear !

=) 2.5x/25 = x/do

=) 2.5x/25 = x/do=) do=25x/2.5x=10cm

=) 2.5x/25 = x/do=) do=25x/2.5x=10cm=) 1/di+1/do=1/f

=) 2.5x/25 = x/do=) do=25x/2.5x=10cm=) 1/di+1/do=1/f=) 1/25 + 1/10 =1/f

=) 2.5x/25 = x/do=) do=25x/2.5x=10cm=) 1/di+1/do=1/f=) 1/25 + 1/10 =1/f=) 7/50=1/f

=) 2.5x/25 = x/do=) do=25x/2.5x=10cm=) 1/di+1/do=1/f=) 1/25 + 1/10 =1/f=) 7/50=1/f=) f=50/7

=) 2.5x/25 = x/do=) do=25x/2.5x=10cm=) 1/di+1/do=1/f=) 1/25 + 1/10 =1/f=) 7/50=1/f=) f=50/7=) f=7.14 cm

Hope , It Helps .

Answer 2

✴OLA!!✴

⤵⤵ANSWER⤵⤵

Magnification (m) = 2.5

distance of the image from the lens (v) = 25cm

distance of the object from the lens (u)= ? (to be calculated)

Focal length of the lens(f) = ? ( to be calculated)

Applying , m = v/u

=> 2.5 = 25/u

=> u = 25/2.5 = 10cm

As u is always negative for a lens , therefore u = -10 cm

Applying , (1/v ) - (1/u) = (1/ f )

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

=> 1/f = 2+5/50 => 7/50

therefore , f = 50/7 = 7.14 cm

Thus , the focal length of the lens is 7.14 cm .✔✔✔

HOPE IT HELPS U✌

Tysm❤