A ray incident on a plane mirror is reflected in a direction such that the angle between the incident and the reflected ray is 90°. What are the angles of incidence and reflection?

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Solution

The law of reflection states that the angle of reflection is equal to the angle of incidence.
i.e., i + r = 90⁰ (given)....... (1)
where, i and r have their usual meaning
Therefore, from the law of reflection, i = r
Now, putting it in equation (1)
=> i + i = 90⁰
=> i = 45⁰
=> r = i = 45⁰

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A ray incident on a plane mirror is reflected in a direction such that the angle between the incident and the reflected ray is 90°. What are the angles of incidence and reflection?

The law of reflection states that the angle of reflection is equal to the angle of incidence. i.e., i + r = 900 (given)....... (1) where, i and r have their usual meaning Therefore, from the law of reflection, i = r Now, putting it in equation (1) => i + i = 900 => i = 450 => r = i = 450

The law of reflection states that the angle of reflection is equal to the angle of incidence.
i.e., i + r = 90⁰ (given)....... (1)
where, i and r have their usual meaning
Therefore, from the law of reflection, i = r
Now, putting it in equation (1)
=> i + i = 90⁰
=> i = 45⁰
=> r = i = 45⁰