Answer the 7th question
Q.7. An object 2 cm high when placed in front of a converging mirror produces a virtual image 3 cm high. If the object is placed at a distance of 8 cm from the pole of the mirror calculate (i) the position of the image (ii) focal length of the converging mirror. ( ans v = 12 cm, f = - 24 cm)

Dear student,

As we know that, 

m = (size of image)/(size of the object) = -v/u  

u = - 8 cm

 3/2 = -v/u 

3/2 = -v/-8 

v = +12 cm

Using mirror formula, 

1/v + 1/u = 1/f  ...(i)

1/12 + 1/(-8) = 1/f 

on solving we get,

f = -24 cm

Regards

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