Question

focal length of a double convex lens is 10cm by using this lens meena wants to get a real and inlarged image at what distance will she place an object in front of lens? plzzzzzz tell me​

Answer 1

Answer:

f=20cm

m=−2(red)

v=2u

Sign convention

u=−ve

v=+ve

f=+ve

Using lens formula,

v1​−u1​=f1​

⇒−2u1​−u1​=f1​

→u=−23f​=−23×10​=−15cm

Object should be placed at 15cm in front of the lens.

Explanation:

Answer 2

Answer:

Explanation:

Definition of lens:

A lens is an optical tool or equipment that, depending on the situation and the type, has a tendency to both converge and diverge a beam of light by refraction.

A compound lens typically consists of numerous simple lenses (elements), which are typically placed along a common axis, as opposed to a simple lens, which often only consists of one transparent piece of material.

Definition of convex lens:

The convex lens, which is relatively thick in the centre and thin at the lower and higher borders, converges light rays that travel parallel to its principal axis (i.e., converges the incident rays towards the principal axis). Instead of curving inside, the edges are curled outward. It is positioned in front of the eye to sharply bend incoming light, shortening the focal point and ensuring optimal illumination of the retina.

Given:

Focal length of double convex lens = $10 cm$

To find:

Object should be placed in front of the lens.

Solution:

$f=10cm$

$v=2u$

Sign convention:

$u = -ve$

$v = +ve$

$f = +ve$

Using lens formula:

$v 1 - u 1 = f 1$

⇒ $- 2 u 1 - u 1 = f 1$

   $- 3 u 1 = f 1$

     $u 1 = - f 1 / 3$

     $u 1 = - 10 / 3$

     $u 1 = - 3.3 cm$

Object should be placed at $- 3.3 cm$ in front of the lens.

#SPJ3