Question

Rohan uses a convex lens to form a real and inverted image of a candle at a distance of 50 cm? where the candle must be placed in front of the convex lens if the image is equal to the size of the object? also find the power of the lens

Answer 1

Answer:

v= 50

u=?

p=?

As image formed by a lens is real and inverted of the same size implies of the object is at 2f.

u=2F =50cm

f=50÷2

= 25cm

P=1÷f(m)

P=100÷25

P= 4D

Answer 2

Let us look at the answer:

Explanation:

As convex lens form a real and inverted image of the same size as that of object. Therefore the object must be placed at 2F and image is also formed at 2F.

⇒ height of object = height of image  that is magnification = 1

Also, u = -50 , v = ? , f = ?

Using lens formula, 1/v -1/u =1/f        ⇒ 1/50- 1/-50 = 1/f

                                                          ⇒2/50 = 1/f

                                                           ⇒ f = 25 cm

power of lens = 1/f (m) = 1/0.25 = 4D