Concepts Of Physics MCQ Edition [Volume 1]PhysicsLight Waves
In air, sodium light has a wavelength of 589 nm . Determine its frequency in water (refractive index = 1.33 ).
Options
- A6.77 10¹⁴ Hz
- B5.89 10¹⁴ Hz
- C5.09 10¹⁴ Hz
- D3.83 10¹⁴ Hz
Correct answer
C. 5.09 10¹⁴ Hz
Step-by-step solution
The frequency of light is a characteristic of the source and remains constant when it travels from one medium to another. Therefore, the frequency of sodium light in water is the same as its frequency in air. Using the relation c = , where c is the speed of light in vacuum and is the wavelength in air: = c = 3 10⁸ 589 10⁻⁹ 5.09 10¹⁴ Hz