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Light Reflection and Refraction
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17/08/2021 4:22 pm
Topic starter
An object 5 cm high is held 25 cm away from a converging lens of focal length 10 cm. Find the position, size and nature of the image formed. Also draw the ray diagram.
1 Answer
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17/08/2021 4:35 pm
\(h_1\) = 5 cm
u = -25 cm
f = 10 cm
\(\frac{1}{v}\) - \(\frac{1}{u}\) = \(\frac{1}{f}\)
\(\frac{1}{v}\) - \(\frac{1}{-25}\) = \(\frac{1}{10}\)
= \(\frac{1}{v}\) = \(\frac{1}{10}\) - \(\frac{1}{25}\)
= \(\frac{5 - 2}{50}\)
= \(\frac{3}{50}\)
v = 16.6
Image is 16.6 cm behind the convex lens.
m = \(\frac{v}{u}\) = \(\frac{\frac{50}{3}}{-25}\)
= -\(\frac{2}{3}\)(Image is real and inverted)
m = \(\frac{h_2}{h_1}\)
= -\(\frac{2}{3}\) = \(\frac{h_2}{5}\)
\(h_2\) = \(\frac{-10}{3}\)
= -3.33 cm
Image is 3.33 cm in size and is real and inverted.