Question

An object 5cm in length os held 25cm aray from the converging lens of focal length 10cm, what is the position and the size of image?

please ans correctly​

Answer 1

Given :-

• Converging lens (convex lens)
• Height of object (ho) = + 5cm
• Object distance (u) = - 25cm
• Focal length (f) = + 10cm

To find :-

• Position of image
• Size of image

Solution :-

According to the Lens formula

→ 1/v - 1/u = 1/f

→ 1/v - (-1)/25 = 1/10

→ 1/v + 1/25 = 1/10

→ 1/v = 1/10 - 1/25

→ 1/v = 5 - 2/50

→ 1/v = 3/50

→ v = 50/3

→ v = + 16.6cm

According to the lens magnification

→ m = v/u = hi/ho

→ v/u = hi/ho

→ 16.6/(-25) = hi/5

→ 16.6 × 5 = -25 × hi

→ 83 = -25hi

→ hi = -83/25 = - 3.3 cm

Hence ,

• Image distance = +16.6cm
• Height of image = - 3.3