Question

An object 5.0 cm in size, is placed 30.0 cm in front of a concave mirror of focal length 15.0 cm.

(1) At what distance from the mirror should sharp image?

(i) Find the size of the image.

(iii) Draw a ray diagram to show the formation of image in this case.​

Answer 1

Explanation:

GIVEN : 1.object size = 5cm .. h = (+5cm )

2.object distance = 30cm .. u = (-30cm)

3. mirror type = concave mirror

4. focal length = 15 cm .. f = (-15cm)

TO FIND : 1.IMAGE DISTANCE = ? .. V = ?

2.SIZE OF IMAGE = ? .. h' = ?

SOLUTION ::

BY MIRROR FORMULA (1/V+1/U=1/F)

=》1/V + 1/U = 1/F

=》1/V + 1/(-30) = 1/(-15)

=》1/V = -1/15 + 1/30

=》1/V = -2+1/30

=》1/V = -1/30

=》V = (-30cm)

BY MAGNIFICATION FORMULA [m = (-v/u)]

WE GET, =》m = -(-30)/(-30)

=》m = (-1)

PUTTING THE VALUE OF MAGNIFICATION IN [ m = h'/h ]

=》 m = h'/h

=》 -1 = h'/(+5)

=》h' = (-5cm)

THEREFORE, THE VALUE OF IMAGE DISTANCE = V = (-30) AND HEIGHT OF THE IMAGE = (-5cm)

HOPE IT HELPS......