Question

Ch-10 (Light)
3 marks question
Q1. A concave lens has focal length of 20 cm. At what distance from the lens a 5 cm tall
object be placed so that it forms an image at 15 cm from the lens? Also calculate the size of
the image formed.
Q2. An object 50 cm tall is placed on the principal axis of a convex lens. Its 20 cm tall image
is formed on the screen placed at a distance of 10 cm from the lens. Calculate the focal
length of the lens.
Q3. Explain with the help of a diagram, why a pencil partly immersed in water appears to be
bent at the water surface.
Q4. The refractive index of water is 1.33 and the speed of light in air is 3 x 108 ms-1.
Calculate the speed of light in water. pls help it's urgent​

koi answer ki photo send Krna pls

Answer 1

Answer:

The distance from lens is 4*15=60cm

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