Question

A convex mirror of focal length f forms an image which is $\frac{1}{n}$ times the object. The distance of the object from the mirror is

• A. (n – 1) f
• B. $\left(\frac{n-1}{n}\right)f$
  
• C. $\left(\frac{n+1}{n}\right)f$
  
• D. (n + 1) f

Answer 1

The correct option is A (n – 1) f

By using $m=\frac{f}{f-u}$
Here $m=+\frac{1}{n},f\to +f$ So, $+\frac{1}{n}=\frac{+f}{+f-u}\Rightarrow u=-(n-1)f$