Question

Magnification produceded
by mirror is m = -2.5.
1 Identify the mirror
b) write the nature of image
c) Guess the position of the
object
d
If the height of the object is
5cm what is the size of the image​

Answer 1

Answer:

1)The mirror is Concave mirror.

2) Nature of the image is real, inverted and enlarged.

3) The position might be more than f (guess)

4) Size or height of the image=  -12.5cm

Explanation:

Since the value of magnification has a negative sign beside it, the image formed is real and inverted. Since the value of the of magnification is more than 1, it means it is an enlarged image of the object that is real and inverted in nature. Height of the object is 5cm

The formula for magnification for a spherical mirror is :

m= -v/u= hi/ho,(where v is the position of the image and u is the image of the object)

hi is the height of the image and ho is the height of the object.

m= -2.5= hi/ 5

= -2.5*5= hi

= -12.5 cm= hi

Since the value of the hi (height of the image formed)  is in negative, this confirms that the image formed is real and inverted.

Position of the image would be,

-v/u= -2.5

-v= -2.5u

v= 2.5u ( Removing negative on both sides)

So the distance of the image from the mirror would be 2.5 times more than the distance of the object from the mirror.

Since u , that is, the distance of the object from the mirror is always a negative value. This means that the image is formed beyond the object.

1/f= 1/v+1/u

1/f= 1/2.5u+1/u

1/f= 10/25u+1/u

1/f= 10/25u+25/25u

1/f= 35/25u

1/f= 7/5u

5u=7f----------(1)

This means that u is more than f  ( f is the focal length of the mirror)

Twice the focal length is the principal center

2f=R

So, in (1)

5*2u= 2*7f

10u= 7R (2f=R) ( where R is the Radius of curvature, R is nothing more than the value of distance)

This tells us that the position of the image is not more than C ( C is the center of curvature, C and f are the two points in the principal axis. The distance of the point f from the mirror is called focal length, it is represented by the same letter f . The distance of the point C from the mirror is called Radius of Curvature, which is represented by the letter R, R is the distance C is the point. Since we are trying to find the position, we only view it as C)

So, this means that the position of the object is not more than C and is more than f.

This means that the position is more than f.