Electromagnetic spectrum

Radio waves, Microwaves, Infrared radiation, Visible light, Ultraviolet radiation, X-rays, Gamma rays. Increasing frequency means decreasing wavelength.

Neither. All electromagnetic waves travel at the same speed in a vacuum (3.0 x 10^8 m/s), regardless of their wavelength or frequency. Therefore, radio waves and microwaves will travel at the same speed.

The remote controller emits a beam of infrared radiation.
Different buttons on the remote produce a unique pattern/code of infrared radiation.
The television receiver detects the infrared signal and interprets the code to perform the corresponding function (

Excessive exposure to microwaves can cause internal heating of body cells. This is because microwaves are absorbed by water molecules in the body, causing them to vibrate and generate heat.

Excessive exposure to UV radiation can cause skin cancer or damage to the eyes, leading to eye conditions such as cataracts.

Distance = Speed x Time
Speed of electromagnetic wave in air ≈ 3.0 x 10⁸ m/s
Time = 5.0 s
Distance = (3.0 x 10⁸ m/s) x (5.0 s) = 1.5 x 10⁹ m

The distance is calculated by multiplying the speed of light in air by the time it travels for.

The approximate speed of electromagnetic waves in air is 3.0 x 10⁸ m/s.

Electromagnetic waves, such as light and radio waves, travel at a very high speed in air, close to their speed in a vacuum.

1. Orbital Height & Coverage: Low orbit satellites are much closer to the Earth, providing limited geographic coverage at any one time, whereas geostationary satellites maintain a fixed position relative to Earth, offering continuous coverage over a large area.
2. Latency: Low orbit satellites exhibit lower latency due to their proximity to Earth, making them better for real-time communication. Geostationary satellites have higher latency due to the longer signal path, which may cause a slight delay. Note: Latency is the delay before a transfer of data begins following an instruction for its transfer.

1. Microwaves can penetrate some walls.
2. Microwaves only require a short aerial for transmission and reception.

(Each correct reason is worth 1 mark.)

Optical fibres are made of glass, which is transparent to visible light and some infrared radiation. Visible light and short wavelength infrared can carry high rates of data, allowing for faster communication and a greater bandwidth than other types of waves (such as radio waves or microwaves).

With an analogue signal, the voltage would vary continuously to match the sound wave's amplitude. The voltage can take any value within the range of the circuit. With a digital signal, the continuous voltage variation is sampled at regular intervals. Each sample is then converted into a binary number (0 or 1 represented by a voltage level). Therefore, the digital signal is a series of discrete binary numbers representing the amplitude of the sound wave at specific times.

1. Analogue signals are continuous, while digital signals are discrete (made of 1s and 0s).
2. Analogue signals are more susceptible to noise/interference than digital signals.

Digital signals can be regenerated/reconstructed. This means that any noise/interference picked up during transmission can be removed, resulting in a clearer sound at the receiving end compared to analogue signals, where noise is amplified along with the original signal. Therefore, digital signals can travel for long distances with minimal signal degradation.

Digital signals can be accurately regenerated at repeater stations along the transmission path. Analogue signals degrade with distance due to noise and attenuation, and any noise is amplified along with the signal by repeaters. Digital signals, being discrete (

1. Increased rate of data transmission: Digital signals can encode more information per unit time. 2. Increased range: Digital signals can be regenerated accurately, reducing signal degradation over long distances.