Question

An object is placed at a distance of 30 cm in front of a concave mirror of focal length 30 cm. The nature of the image produced is??

Please answer quickly!!
Spam answers will be reported on the spot!!

Answer 1

Given:

• Object distance (u) = 30 cm
• Focal length (f) = 30

To Find:

• The nature of the image produced

Solution:

According to the sign convention:

• The object distance is always taken negative.
• The focal length of a concave mirror is always taken negative.

Therefore:

• Object distance (u) = -30 cm
• Focal length (f) = -30 cm

We know,

Mirror formula:

• $\dag{\boxed{\sf{\dfrac{1}{f} = \dfrac{1}{v} + \dfrac{1}{u}}}}$

Hence,

$\sf{\dfrac{1}{-30} = \dfrac{1}{-30} + \dfrac{1}{v}}$

$= \sf{\dfrac{1}{-30} + \dfrac{1}{30} = \dfrac{1}{v}}$

$= \sf{\cancel{\dfrac{-1}{30}} + \cancel{\dfrac{1}{30}} = \dfrac{1}{v}}$

$= \sf{\dfrac{1}{v} = 0}$

$\implies \sf{v = \dfrac{1}{0}\:or\:infinity}$

∴ The image is formed at the infinity.

We know, when an image is formed at infinity the size of the image is highly enlarged and the image is real and inverted.

∴ The nature of the image formed is real and inverted.

______________________________________

Explore More!!

There is another way to answer this question according to the ray diagrams.

• We know, according to the ray diagram (5th Ray diagram) when the object is placed on the focal length of the concave mirror, the image is formed at infinity and the size of the image is highly enlarged and the nature of the image is real and inverted.

______________________________________