Answer to Question #77452 in Optics for ugoeze anene

Question

A concave shaving mirror has a focal length
of 36 cm.
a) Calculate the image position of a cologne
bottle placed in front of the mirror at a distance
of 76 cm. (Answer with −1000 if the
image does not exist.)
Answer in units of cm.

Answer 1

According to the mirror equation
1/a+1/b=1/f,
where a – is the distance of the object to the surface of the mirror; b – is the distance of the image to the surface of the mirror; f – is the focal length.
We have
1/b=1/f-1/a ⇒ b=1/(1/f-1/a)=1/(1/36-1/76)=68.4 cm