Question

An image of an object produced on a screen which is about 36 cm using a convex lens.The image produced is about 3 times the size of the object. What is the size of the object?

12 cm
33 cm
39 cm
108 cm​

Answer 1

Given info : An image of an object produced on a screen which is about 36 cm using a convex lens.The image produced is about 3 times the size of the object.

To find : the size of the object is ...

solution : ∵  the image produced is about 3 times the size of the object.

∴ the size of image = 3 × the size of object

⇒ 36 cm = 3 × the size of object

⇒ the size of object = 36/3 = 12 cm

Therefore the size of the object is 12cm.

useful information :

• convex lens is converging lens.
• the focal length of convex lens is considered as positive.
• a convex lens can produce real and virtual images.
• this lens is used to make microscopes , telescopes cameras and other magnifying glasses.
• it is used in eyeglasses for correcting far-sightedness.

Answer 2

Answer:

a) 12cm

Explanation:

M=h'/h

3=36/h

h=36/3

h = 12cm

tips:- To do it faster if process is not required then just see that how much times is the size of image is bigger. like this if it is 3 times then divide the image size with 3...

hope it helped u all...