Calculate the energy of the lasers in a Blu-ray player, which emit at a wavelength of 4.05x10−7 m.

4.907 × 10^-19 J

Explanation:

The energy of the lasers in a Blu-ray player can be calculated by using;

E = hf

Where;

E = Energy of laser (J)

h = Planck's constant (6.626 × 10^-34 J/s)

f = frequency (Hz)

However, the frequency must be known first in order to calculate the energy. The frequency can be calculated using the formula:

f = v/λ

Where:

λ = wavelength (4.05x10−7 m.)

v = speed of light (3 × 10^8m/s)

f = frequency (Hz)

f = 3 × 10^8 ÷ 4.05 x 10^−7

f = 0.7407 × 10^(8 + 7)

f = 0.7407 × 10^15

f = 7.407 × 10^14 Hz

Using E = hf

E = 6.626 × 10^-34 × 7.407 × 10^14

E = 49.07 × 10^(-34 + 14)

E = 49.07 × 10^-20

E = 4.907 × 10^-19 J