Question

Enter the following measures of length in the place value chart 7km 2hm 8 dam 6m 2dm 9cm 5mm​

Answer 1

Step-by-step explanation:

Given: A converging lens and a converging mirror are placed with their principal axis coinciding. Their separation equals 40cm. A point source S is placed on the principal axis at a distance of 2cm from the lens as shown in the figure. It is found that the final beam comes out parallel to the principal axis. The focal length of the lens equals 5cm.

To find the focal length of the mirror.

Solution:

First consider converging lens,

As per the given criteria,

object distance, u=−2cm

focal length of the lens, f=5cm

Applying the lens formula, we get

f

1

=

v

1

−

u

1

⟹

5

1

=

v

1

−

(−2)

1

⟹

v

1

=

5

1

−

2

1

⟹

v

1

=

10

2−5

⟹v=−3.33cm

So the image of the point source object formed by the converging lens is 3.33 cm from the lens on the same side as the object.

This forms object for the converging mirror.

Now will consider converging mirror,

As the distance between the lens and mirror is 40cm.

So the object distance for the mirror is u

′

=(40+3.33)=43.33cm

as the final beam comes out is parallel to the principal axis, the image is formed at infinity.

So the image distance, v

′

=∞

Applying the mirror formula, we get

f

′

1

=

v

′

1

+

u

′

1

⟹

f

′

1

=

∞

1

+

43.33

1

⟹f

′

=43.33cm

is the focal length of the mirror.

Solve any question of Ray Optics and Optical Instrument with:-