Answer the following:
  
What is meant by magnification? Write its expression. What is its sign for real image and virtual image?
 
Magnification can be defined as the ratio of the to the .
 
The presence of a negative sign in the magnification value indicates that the image is .
 
The presence of a positive sign in the magnification value indicates that the image is .
 
\(m>1\) - The image formed is .
 
\(m<1\) - The image formed is .