A certain type of laser emits light that has a frequency of 4.9 x 1014 Hz. The light, however, occurs as a series of short pulses, each lasting for a time of 2.9 x 10-11 s. The light enters a pool of water. The frequency of the light remains the same, but the speed of light slows down to 2.3 x 108 m/s. In the water, how many wavelengths are in one pulse

Respuesta :

Answer:

N = 1.42 × 10⁴ cycles

Explanation:

Given that:

frequency f = 4.9 × 10¹⁴ Hz

Time = 2.9 × 10⁻¹¹ s

Speed = 2.3 × 10⁸ m/s

Recall that:

wavelength [tex]\lambda = \dfrac{c}{f} \\ \\[/tex]

Horizontal distance [tex]\Delta x = ct[/tex]

Number of wavelengths [tex](N) = \dfrac{\Delta x}{\lambda}[/tex]

[tex]N = \dfrac{ct}{c/f} \\ \\ N= ft[/tex]

N = (4.9 × 10¹⁴ cycles/s) (2.9 × 10⁻¹¹ s)

N = 14210

N = 1.42 × 10⁴ cycles