Question

an object is 2 cm high is placed at a distance of 64 cm from the screen on placing a convex lens 32 cm from the object it is found that a distant image of the object is formed on the screen find the focal length of the cinvex lens and size of the image​

Answer 1

Determination of focal length of the lens:

From the lens formula, 

1f=1v-1u     =164-32-1-32     =132+132     =232f=322  =16 cm

Determination of the size of the image:

From the formula of magnification,

m=h2h1=vuh2=vu×h1    =32-32×2    = -2 cm

Here, the negative sign of image size represent that the image is inverted.

Ray diagram to show the formation of lens:

diagram is on the description...

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