Question

for a mirror m= v/u and for lens m = -v/u​

Answer 1

Answer:

According to the question,

Image distance, v=−15 cm (negative due to convex lens)

Focal length, f=−20 cm

Let the object distance be u.

• By lens formula:
• v1−u1=f1[4pt]
• ⇒−15 cm1−u1=−20 cm1[4pt]
• ⇒u1=20 cm1+−15 cm1[4pt]
• ⇒u1=60 cm3−4=60 cm−1[4pt]
• ⇒u=−60 cm

Therefore, object is placed at 60 cm away from the lens, on the same side as image.

Now,

Height of object, h1=5cm

Magnification, m=h1h2=uv

Putting value of