If a light ray travels from denser to rarer medium. Which of the following statement/s are correct?

(A) Energy increases

(B) Frequency remain same

(C) Phase changes by 90°

(D) Velocity increases

(E) Wavelength decreases

Choose the correct answer from the options given below :

Explanation:

When a light ray travels from a denser to a rarer medium, it undergoes refraction, and several properties of the light wave change. The properties that change include the velocity, wavelength, frequency, and phase.

Energy increases:

This statement is incorrect. Energy is conserved, and it remains constant as light travels from one medium to another. However, some energy may be lost due to absorption or reflection.

Frequency remains the same:

This statement is correct. The frequency of the light wave remains constant as it moves from one medium to another.

Phase changes by 90°:

This statement is incorrect. The phase change depends on the angle of incidence and the angle of refraction, and it varies for different angles. It may or may not change by 90°.

Velocity increases:

This statement is correct. The velocity of light increases as it moves from a denser to a rarer medium. This is because the refractive index of the rarer medium is less than the denser medium, and the speed of light is directly proportional to the refractive index.

Wavelength decreases:

This statement is incorrect. The wavelength of the light wave changes as it moves from one medium to another. Snell's law gives the relationship between the wavelength and the refractive index. However, the change in wavelength depends on the angle of incidence and the angle of refraction and is not a fixed value.

In conclusion, option 2 is the correct answer, as only statements (B) and (D) is correct.

The correct answer is option (2)