Question

Solve the upper one question..​

Answer 1

Given :-

◉ An object of height h₀ = 4 cm is placed at a distance of u = -25 cm from a concave mirror.

◉ Focal length of the spherical mirror is f = -15 cm

To Find :-

◉ Distance at which a screen should be placed to obtain a sharp image.

◉ Nature and size of the image.

Solution :-

Distance at which screen should be placed in order to obtain sharp image is the distance at which the image is formed.

Let us find the distance of image.

We know,

⇒ 1/f = 1/v + 1/u

⇒ -1/15 = 1/v - 1/25

⇒ 1/v = 1/25 - 1/15

⇒ 1/v = (3 - 5)/75

⇒ 1/v = -2/75

⇒ v = -37.5 m

Hence, The screen should be put at a distance of 37.5 m from the concave mirror in order to obtain a sharp image.

Now, Let us find the Magnification in order to know the properties of the image formed.

⇒ m = -v/u

⇒ m = -(-37.5/-25)

⇒ m = -37.5/25

⇒ m = -1.5

Negative magnification indicates that the position of the image is on the left side of mirror or in the direction of object. Also, If it is negative, It means the image is real and inverted.

So, Properties of Image :-

• Size : 1.5 times the object size.
• Position : In the direction of object, 37.5 m crom the mirror.
• Nature : Real and Inverted.