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  • You are provided with a convex mirror, a concave mirror, and a convex lens. Using the parallax method, determine the focal lengths of these optical devices. For each case, the object is placed at a

You are provided with a convex mirror, a concave mirror, and a convex lens. Using the parallax method, determine the focal lengths of these optical devices. For each case, the object is placed at a certain distance, and you observe the apparent shift when viewing the object through the optical device from different angles.

Given:

• Distance between the object and the optical device, Do = 60 cm
• Apparent shift of the object, d = 3 cm
• Distance between your eyes and the optical device, De = 30 cm


Assumptions:
• The optical devices are properly aligned and centered.
• For convex mirror and lens, the object is virtual.

Option: 1

20 cm, -20 cm , 20 cm


Option: 2

-20 cm, -20 cm , 20 cm


Option: 3

c) 20 cm, 20 cm , 20 cm


Option: 4

20 cm, -20 cm , -20 cm


Answers (1)

best_answer

For Convex Mirror:
1. Apply the parallax method formula to calculate the focal length (f) of the convex mirror:

f= \frac{D_{o}. De}{D_{o}-D_{e}}
2. Substitute the given values into the formula:

f= \frac{60 cm. 30cm}{60cm- 30 cm}

3. Calculate the focal length:

f = −20 cm

 

For Concave Mirror:
1. Apply the same parallax method formula to calculate the focal length (f)
of the concave mirror:

f= \frac{D_{o}. De}{D_{o}-D_{e}}
2. Substitute the given values into the formula:

f= \frac{60 cm. 30cm}{60cm- 30 cm}

3. Calculate the focal length:

f = −20 cm

 

For Convex Lens:
1. Apply the parallax method formula to calculate the focal length (f) of the
convex lens:

f= \frac{D_{o}. De}{D_{o}+D_{e}}
2. Substitute the given values into the formula:

f= \frac{60 cm. 30cm}{60cm+ 30 cm}

3. Calculate the focal length:

f = 20 cm

The focal lengths of the optical devices, determined using the parallax method, are as follows:
• For the convex mirror: f = −20 cm
• For the concave mirror: f = −20 cm
• For the convex lens: f = 20 cm
The parallax method involves observing the apparent shift in the position of the object when viewed through the optical device from different angles. By measuring the distances and applying the parallax formula, you can calculate the focal lengths of the devices.
So, option A is correct

Posted by

Kuldeep Maurya

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