Question

A CONVEX LENS HAS FOCAL LENGTH OF 10 CM. AT WHAT DISTANCE LENS SHOULD BE PLACED SO IT FORMS REAL AND INVERTED IMAGE?IF OBJECT IS 20 CM AWAY FROM LENS. WHAT IS SIZE OF IMAGE IF LENS IS 2 M HIGH? DRAW RAY DIAGRAM

PLS SOLVE IT FAST I WILL MARK YOUR ANSWER AS BRAINLIEST​

Answer 1

CORRECT QUESTION :-

A convex lens has a focal length of 10 cm. At what distance from the lens should the object be placed so that it forms real and inverted image if the image is 20 cm away from the lens? What would be the size of the image formed if the object is 2 cm high? Draw a ray diagram.

GIVEN :-

• Focal length, f = 10 cm             } Positive in a convex lens.

• Image distance, v = 20 cm      } Positive in a convex lens.

• Object size, $\sf{h_o}$ = 2 cm

• Image produced is real and inverted.

TO FIND :-

The object distance(u) and the image size( $\sf{h_i}$ ).

FORMULA TO BE USED :-

Lens formula :-

$\bigstar\ \sf{\dfrac{1}{v}-\dfrac{1}{u}=\dfrac{1}{f}}$

$\bigstar\ \sf{Magnification=\dfrac{-v}{u}=\dfrac{h_i}{h_o} }$

SOLUTION :-

Using the Len's formula :-

$\sf{\dfrac{1}{20}-\dfrac{1}{u}=\dfrac{1}{10}}\\\\\\\sf{\implies \dfrac{1}{20}-\dfrac{1}{10}=\dfrac{1}{u}}\\\\\\\sf{\implies \dfrac{1-2}{20}=\dfrac{1}{u} }\\\\\\\sf{\implies \dfrac{-1}{20}=\dfrac{1}{u} }\\\\\\\large\boxed{\sf{\implies u=-20\ cm }}$

$\rule{120}{2}$

Now,

$\sf{Magnification=\dfrac{-v}{u}=\dfrac{h_i}{h_o} }$

$\sf{\implies \dfrac{-v}{u}=\dfrac{h_i}{h_o} }$

$\sf{\implies \dfrac{-20}{-20}=\dfrac{h_i}{2} }\\\\\\\sf{\implies h_i=\dfrac{2}{1} }\\\\\\\large\boxed{\sf{\implies h_i=2\ cm }}$

Answer 2

Explanation:

f = 10 cm , u = 20 cm ,h(o) = 2m

TRICK

• Here the object is placed at the centre of curvature ( ie, 2f ) in front of a convex lens.So its image is formed at the centre of curvature on the other side of the lens with  

• The image formed is real, inverted
• Height of image same is size as that of object.

I hereby attach the image .

                            Hope u understand

                          Isn't it the Brainliest