Question

An object is placed in front of concave mirror of focal length 10cm.if image is formed is double the Height of object,find out position of object from pole

Answer 1

Answer:

Explanation:

It is a concave mirror..so

Focal length,f=-10cm

According to the given condition;

Size of object=2 size of object

We know that, magnification,

m=size of image/size of object=2

We also know that m= -v/-u

Therefore,v=2u.

Now substituting this value in mirror equation

ie.1/f=1/v+1/u..we get

-1/10 =1/2u +1/u

Solving this we get,u=-15..

In concave mirror u is negative, so u=15..

Hope it's helpful.

Answer 2

Answer:

-10 cm

Explanation:

Given f=-20cm m=+2 because the image is virtual and erect.