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A radio transmitter operates at a frequency 880 kHz and a power of 10 kW. The number of photons emitted per second is:

1. 1.72 × 10³¹
2. 1.327 × 10³⁷
3. 1.327 × 10²⁵
4. 1.327 × 10⁴⁵

Correct answer: 1.327 × 10²⁵

Solution

The energy of one photon is given by E = hν, where h is Planck's constant and ν is the frequency. The total energy emitted per second is the power, P. Dividing P by E gives the number of photons emitted per second. Substituting the values, the result is approximately 1.327 × 10²⁵.

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