Question

When a ray of light enters from air into water then its wavelength:
(A) decreases
(B) increases
(C) remains unchanged
(D) becomes infinity

Answer 1

Hint When the ray of the light enters from one medium to the other medium, some parameters will become the same and some parameters will change. If the ray of light is entering from air into water some parameters of the light will be the same and some are different.

Complete step by step solution
Given that,
When a ray of light enters from air into water.
The Wavelength of the is characterized as the property of a wave in which the separation between the identical points between the two progressive waves are determined. It is indicated by the Greek letter lambda . Consequently, the separation between it is possible that one peak of one wave and the following wave is known as Wavelength. The wavelength of the light is characterized as "The separation between the two progressive peaks or box of the light wave".
The beam of light twists towards the normal. When a beam of light enters from an optically more uncommon medium (having low refractive list) to an optically denser medium (having high refractive list), its speed will be decreasing and it twists towards the normal. Since water is optically denser than air, a beam of light entering from air into water will twist towards the typical. So, when the light enters the water from the air, the energy of the light rays will remain the same, its frequency also will remain the same, But the speed of the light is decreasing, so that the wavelength of the light also decreases.

Hence, the option (A) is the correct answer.

Note The speed of the light is directly proportional to the wavelength of the light. As the speed of the light is increasing then the wavelength of the light also increases. As the speed of the light is decreasing then the wavelength of the light also decreases.