An object is placed in front of concave mirror of focal length 20cm the image formed is three times the size of the object .calculte two possible distances of the object from the mirror?

Question

Answer

Answer

Explanation:

The given focal length of the concave mirror is 20cm.

The magnification of the image formed is 3 times the size of the object.

We need to find two possible distances of the object from the mirror.

Formula:

Magnification (m) = -v/u

focal length (f) = (1/2) * (R)

where,

v = image distance from the mirror

u = object distance from the mirror

R = radius of curvature

m = magnification

Solution:

Let us assume the distance of the object from the mirror to be 'u'.

Given magnification (m) = 3 times the size of the object.

Hence, m = -v/u = 3

From the above formula, we can find v as follows:

v = -3u

Now, we can use the formula for the focal length:

f = (1/2) * (R)

Given f = 20cm, we can find R as follows:

R = 2 * f = 40cm

Using the formula for the mirror equation:

1/u + 1/v = 1/f

Substituting the values, we get:

1/u + 1/(-3u) = 1/20

Solving for u, we get:

u = 15cm or -5cm

Since the object cannot be placed behind the mirror, we reject the negative value of u.

Hence, the possible distances of the object from the mirror are:

u1 = 15cm

We can also find the second possible distance of the object from the mirror by changing the magnification:

Let us assume the new magnification (m) to be 1.5 times the size of the object.

Using the same formula for mirror equation and solving for u, we get:

u2 = 30cm

Answer

I think info is incomplete...!there must be either object dostance or image distance only then it can be solve...)

Answer

No this is correct

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