Question

An object is placed at the distance of 10cm in front of concave mirror focal length of mirror is 5 cmfind image position

Answer 1

Given :

▪ Distance of object = 10cm

▪ Focal length of mirror = 5cm

▪ Type of mirror : Concave

To Find :

▪ Diastance of image.

Concept :

↗ X-coordinates of centre of curvature and focus of concave mirror are negative and those for convex mirror are positive. In case of mirrors since light rays reflects back in X-direction, therefore -ve sign of v indicates real image and +ve sign of v indicates virtual image.

✴ Mirror Formula :

$\bigstar\:\underline{\boxed{\bf{\red{\dfrac{1}{u}+\dfrac{1}{v}=\dfrac{1}{f}}}}}$

Calculation :

☞ 1/u + 1/v = 1/f

☞ 1/(-10) + 1/v = 1/(-5)

☞ 1/v = -1/5 + 1/10

☞ 1/v = (-2+1)/10

☞ 1/v = -1/10

☞ v = -10cm

Answer 2

Given:-

• Object distance (u) = -10 cm

• Focal length (f) = -5 cm

To Find:-

• Image position (v) .

Solution :-

By using Mirror Formula.

➦ 1/u +1/v =1/f

➭ 1/(-10) + 1/v = 1/(-5)

➭ 1/v = 1/(-5) + 1/(10)

➭ 1/v = -1/5 + 1/10

➭ 1/v = -2+1/10

➭ 1/v = -1/10

➭ v = -10cm

∴ The image position is -10cm.