Question

An object 1.00cm high is placed 18.0cm from a converging lens, forms a real Image 2.00cm high Calculate the forcal length of to the lens

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Answer 1

focal length=12cm

Step-by-step explanation:

object size is equal to 1.00cm

object distance = 18cm

heigh of image = 2.00cm

image distance = ??

but magnification is given by;

M = 2.00/1.00 = 2

but u/v = M

u/18 = 2

u = 36

1/f = 1/u+1/v

1/f = 1/18+ 1/36

1/f = 1/12

f = 12cm