Question

1:
The focal length of a concave mirror is f and the distance from the object to the prin
is x. Then find the ratio of the size of the image to the size of the object.​

Answer 1

Answer:

Explanation:

Distance of object is u=−(f+p)

v

1

​  

+  

u

1

​  

=  

f

1

​  

 gives:

v

1

​  

−  

f+p

1

​  

=−  

f

1

​  

 

or,  

v

1

​  

=−  

f

1

​  

+  

f+p

1

​  

 

or,  

v

1

​  

=−  

(f+p)×f

p

​  

 

or, v=−  

p

(f+p)×f

​  

 (-ve sign indicates image is real)

Magnification =−  

u

v

​  

 

=−  

p×(f+p)

(f+p)×f

​  

 

=−  

p

f

​  

 (-ve sign indicates inverted)

So, ratio of size of image to that of object is: −  

p

f

​