9.1 Define an electromagnetic wave - NSC Technical Sciences - Question 9 - 2020 - Paper 2

They have longer wavelengths.

A photon is a quantum (packet) of energy.

Infrared.

Ultraviolet.

Radio waves.

Wavelength and frequency are inversely proportional. When wavelength becomes longer, frequency decreases.

To calculate the energy, we use the formula:

$E = \frac{c}{\lambda}$

Where:

• $c = 3.0 \times 10^8 \text{ m/s}$ (speed of light)
• $\lambda = 4.06 \times 10^{-11} \text{ m}$

Calculating frequency:

$f = \frac{c}{\lambda} = \frac{3.0 \times 10^8}{4.06 \times 10^{-11}} = 7.39 \times 10^{18} \text{ Hz}$

Now, using the formula for energy:

$E = hf$

Where:

• $h = 6.63 \times 10^{-34} \text{ Js}$

Thus:

$E = 6.63 \times 10^{-34} \times 7.39 \times 10^{18} \approx 4.89 \times 10^{-15} \text{ J}$