An object 5 cm in length is held 25 cm away from a converging lens of focal length 10 cm. Draw the ray diagram and find the position, size and the nature of the image formed.
Object distance, u = −25 cm
Object height, ho = 5 cm
Focal length, f = +10 cm
According to the lens formula,
The positive value of v shows that the image is formed at the other side of the lens.
Magnification m =`-"image distance"/"object distance"=-v/u=16.66/25=-0.66`
The negative sign shows that the image is real and formed behind the lens.
Magnification m =`"image height"/"object height"=H_i/H_o=H_i/5`
Hi=m x Ho=-0.66 x 5=-3.3 cm
The negative value of image height indicates that the image formed is inverted.The position, size, and nature of image are shown in the following ray diagram.
Object distance, u =-25 cm
Focal length, f = 10 cm
Height of the object, h = 5 cm
Applying the lens formula, we get:
⇒`v=50/3=+16.6 ` cm
The image will be at a distance of 16.6 cm behind the lens.
Thus, the image will be 3.3 high. It will be real and inverted
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