Question of optics see image

Dear Student,

g i v e n, f = 10 c m u = - 15 c m w e k n o w, \frac{1}{v} - \frac{1}{u} = \frac{1}{f} \Rightarrow \frac{1}{v} = \frac{1}{f} + \frac{1}{u} \Rightarrow \frac{1}{v} = \frac{1}{10} - \frac{1}{15} \Rightarrow v = 30 c m t h e r e f r a c t e d r a y s f r o m l e n s s h o u l d f a l l n o r m a l l y o n t h e m i r r o r f o r t h e i m a g e t o c o i n c i d e w i t h t h e o b j e c t . d + 20 = v = 30 c m d = (30 - 20) c m = 10 c m

Regards