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A ray of light falls on a plane mirror and the mirror is turned about an Axis at right angles to the plane of mirror by 20 degree the angle between the incident ray and the new reflected ray is 45 degree. angle between the incident ray and original reflected ray was therefore. a. 35 or 50. b. 25 or 65. C. 45 or 5. D. None of these?
Verified Answer
A ray of light falls on a plane mirror and the mirror is turned about ...
The mirror rotation around the axis perpendicular to the mirror plane doesn't change an incident angle and therefore, does not change the reflected ray either. the rotation occurs about the normal to the mirror, therefore the point of incidence remains the same too, hence the reflected ray remains unchanged.
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Most Upvoted Answer
A ray of light falls on a plane mirror and the mirror is turned about ...
Given:
- A ray of light falls on a plane mirror.
- The mirror is turned about an axis at right angles to the plane of the mirror by 20 degrees.
- The angle between the incident ray and the new reflected ray is 45 degrees.

To find:
The angle between the incident ray and the original reflected ray.

Solution:

Let's analyze the situation step by step:

Step 1: Incident Ray and Normal to the Mirror
- When a ray of light falls on a mirror, the angle between the incident ray and the normal to the mirror is called the angle of incidence.
- Let's assume the angle of incidence is 'x'.

Step 2: Reflection of Incident Ray
- According to the laws of reflection, the angle of reflection is always equal to the angle of incidence.
- So, the angle between the reflected ray and the normal to the mirror is also 'x'.

Step 3: Mirror Rotation
- The mirror is then turned about an axis at right angles to the plane of the mirror by 20 degrees.
- This means the mirror is rotated by 20 degrees clockwise or counterclockwise.
- Let's assume the rotation is clockwise.

Step 4: New Normal to the Mirror
- After rotation, the normal to the mirror will also rotate by 20 degrees clockwise.
- The new normal will make an angle of (x + 20) degrees with the original normal.

Step 5: New Reflection of Incident Ray
- The new reflected ray will be in the direction of the new normal to the mirror.
- The angle between the incident ray and the new reflected ray is given as 45 degrees.

Step 6: Finding the Angle between Incident Ray and Original Reflected Ray
- To find the angle between the incident ray and the original reflected ray, we need to subtract the rotation angle (20 degrees) from the angle between the incident ray and the new reflected ray (45 degrees).
- So, the angle between the incident ray and the original reflected ray is (45 - 20) = 25 degrees.

Answer:
Therefore, the angle between the incident ray and the original reflected ray is 25 degrees. Hence, the correct option is (b) 25 or 65.
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A ray of light falls on a plane mirror and the mirror is turned about an Axis at right angles to the plane of mirror by 20 degree the angle between the incident ray and the new reflected ray is 45 degree. angle between the incident ray and original reflected ray was therefore. a. 35 or 50. b. 25 or 65. C. 45 or 5. D. None of these?
Question Description
A ray of light falls on a plane mirror and the mirror is turned about an Axis at right angles to the plane of mirror by 20 degree the angle between the incident ray and the new reflected ray is 45 degree. angle between the incident ray and original reflected ray was therefore. a. 35 or 50. b. 25 or 65. C. 45 or 5. D. None of these? for JEE 2024 is part of JEE preparation. The Question and answers have been prepared according to the JEE exam syllabus. Information about A ray of light falls on a plane mirror and the mirror is turned about an Axis at right angles to the plane of mirror by 20 degree the angle between the incident ray and the new reflected ray is 45 degree. angle between the incident ray and original reflected ray was therefore. a. 35 or 50. b. 25 or 65. C. 45 or 5. D. None of these? covers all topics & solutions for JEE 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A ray of light falls on a plane mirror and the mirror is turned about an Axis at right angles to the plane of mirror by 20 degree the angle between the incident ray and the new reflected ray is 45 degree. angle between the incident ray and original reflected ray was therefore. a. 35 or 50. b. 25 or 65. C. 45 or 5. D. None of these?.
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