Question

Мощность излучения лазерной указки с частотой 5*10^14 с^-1 равна 5 мВт. Определить число фотонов, излучаемых указкой за 40 секунд. Постоянная планка 6.63*10^-34, скорость света в вакууме 3*10^8.

Answer 1

Ответ:

Объяснение:

Дано:

P = 5 мВт = 5·10⁻³ Вт

ν = 5·10¹⁴ Гц

t = 40 с

____________

N - ?

1)

Энергия указки:

E = P·t = 5·10⁻³·40 = 0,20 Дж

2)

Энергия одного фотона:

ε = h·ν = 6,63·10⁻³⁴·5·10¹⁴ ≈ 3,32·10⁻⁹ Дж

3)

Число излучаемых фотонов:

N = E / ε = 0,20 / (3,32·10⁻⁹) ≈ 6·10¹⁷

Answer 2

Calculation of the Number of Photons Emitted by a Laser Pointer

To determine the number of photons emitted by a laser pointer, we need to use the formula that relates the power of the laser to the number of photons emitted per second. The formula is given by:

Number of photons emitted per second = Power of the laser / Energy of a single photon

The energy of a single photon can be calculated using the equation:

Energy of a single photon = Planck's constant * Frequency of the laser

Given: - Power of the laser = 5 mW - Frequency of the laser = 5 * 10^14 s^-1 - Planck's constant = 6.63 * 10^-34 J·s

Let's calculate the number of photons emitted by the laser pointer.

Calculation:

First, let's calculate the energy of a single photon using the given frequency and Planck's constant:

Energy of a single photon = (6.63 * 10^-34 J·s) * (5 * 10^14 s^-1)

Now, let's calculate the number of photons emitted per second using the power of the laser and the energy of a single photon:

Number of photons emitted per second = (5 mW) / (Energy of a single photon)

Finally, to determine the number of photons emitted by the laser pointer in 40 seconds, we multiply the number of photons emitted per second by the duration:

Number of photons emitted in 40 seconds = (Number of photons emitted per second) * (40 seconds)

Let's perform the calculations:

Solution:

Using the given values, we can calculate the number of photons emitted by the laser pointer.

1. Energy of a single photon: - Energy of a single photon = (6.63 * 10^-34 J·s) * (5 * 10^14 s^-1) - Energy of a single photon = 3.315 * 10^-19 J

2. Number of photons emitted per second: - Number of photons emitted per second = (5 mW) / (Energy of a single photon) - Number of photons emitted per second = (5 * 10^-3 J/s) / (3.315 * 10^-19 J) - Number of photons emitted per second ≈ 1.509 * 10^16 photons/s

3. Number of photons emitted in 40 seconds: - Number of photons emitted in 40 seconds = (Number of photons emitted per second) * (40 seconds) - Number of photons emitted in 40 seconds ≈ (1.509 * 10^16 photons/s) * (40 seconds) - Number of photons emitted in 40 seconds ≈ 6.036 * 10^17 photons

Therefore, the laser pointer emits approximately 6.036 * 10^17 photons in 40 seconds.

Please note that the above calculations are based on the given values and assumptions.