Q5 of 13 Page 127

Solve the following examples

A 10 cm long stick is kept in front of a concave mirror having focal length of 10 cm in such a way that the end of the stick closest to the pole is at a distance of 20 cm. What will be the length of the image?


According to the question;

Focal length (f) = -10cm;


Length of stick (Lo) = 10cm;


Length of image = Li;


Object distance (u) = -20cm;


By mirror formula;







⇒ v = -20.


Since v = - 20 cm which is negative hence image is at left side of mirror.


Now


Magnification = =


Putting values of v and u .


Magnification =


=


Negative sign means image is inverted.



Hence Li = Lo .


Hence length of image is 10 cm


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