Question

The focal length of a convex mirror is 12.5cm How far is its centre of curvature from the
i) pole of the mirrow
ii) focus of mirror

Class 10​

Answer 1

AnswEr :

• The centre of curvature from the pole is 25cm.
• The centre of curvature from the focus is 12.cm.

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Given :

• The focal length of a convex mirror is 12.5cm.

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Unknown :

• The centre of curvature from the pole.
• The centre of curvature from the focus.

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Calculations :

Here in this question we are given with the focal length of a convex mirror and we are asked to calculate the centre of curvature from the pole and the centre of curvature from the focus. So we can easily calculate the centre of curvature from the pole, it means the radius of curvature by twicing the focal focal length. And also we know that the distance between Center of curvature from the focus is equal to the focal length, so by here we can also find out the centre of curvature from the focus. So let's solving our problem and understanding the steps to get our final answer. Let's do it...!!

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i) The centre of curvature from the pole (the radius of curvature or R) :

We know that, the by twicing the focal focal length we can get the centre of curvature from the pole or the radius of curvature or R.

→ R = 2 * f

→ R = 2 * 12.5

→ R = 25cm.

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ii) The centre of curvature from the focus :

We know that, distance between center of curvature from the focus is equal to the focal length.

→ R = 12.5cm.

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Hence, the centre of curvature from the pole and the focus is 25cm and 12.5cm respectively.

Answer 2

Question:-

• The focal length of a convex mirror is 12.5cm How far is its centre of curvature from the pole of the mirror and focus of mirror.

To Find:-

• How far is its centre of curvature from the pole of the mirror and focus of mirror.

Solution:-

Given ,

• The focal length of the convex mirror is 12.5 cm.

First ,

We have to find the centre of curvature from the pole of the mirror:-

$\dashrightarrow\sf \: R = 2 \times f$

$\dashrightarrow\sf \: R = 2 \times 12.5$

$\dashrightarrow\sf \: R = 25 \: cm$

Now ,

We have to find the focus of the mirror:-

$\dashrightarrow\sf \: Focus \: of \: mirror = focal \: length$

$\dashrightarrow\sf \: Focus \: of \: mirror = 12.5 \: cm$

Hence ,

• Focus of mirror is 12.5 cm.