Question

Which of the following electromagnetic waves is used in telecommunication? (A) radiowaves (B) visible radiations (C) ultraviolet rays (D) microwaves

Short answer

The correct answer is (A) radio waves, as they have the longest wavelength among the given options and are widely used in communication systems such as radio and television broadcasting, and wireless communication devices like cellphones and Wi-Fi.

Step-by-step solution

1. Understand the different types of electromagnetic waves

electromagnetic waves can be classified into several types, such as radio waves, visible light, ultraviolet radiation, and microwaves. Each type of wave has different properties and uses.

2. Analyze the application of radio waves

Radio waves have the longest wavelength among the given options and have frequencies ranging from 3 kHz to 300 GHz. They are widely used in communication systems such as radio and television broadcasting, and wireless communication devices like cellphones and Wi-Fi.

3. Analyze the application of visible radiations

Visible radiations consist of light that can be seen by the human eye, having wavelengths in the range of 400-700 nm. While they play a crucial role in everyday life, they are not primarily used for telecommunication purposes.

4. Analyze the application of ultraviolet rays

Ultraviolet rays have shorter wavelengths than visible light, ranging from about 100 to 400 nm. They are mainly responsible for the production of vitamin D in our skin and are also used in sterilization processes. However, they are not used in telecommunication.

5. Analyze the application of microwaves

Microwaves have wavelengths ranging from 1 millimeter to 100 centimeters, and are mainly used for cooking in microwave ovens. In addition, they are used in radar systems and satellite communication, making them relevant to the field of telecommunication.

6. Choose the correct answer

Based on the analysis of the applications of the electromagnetic waves provided, it is clear that both radio waves (A) and microwaves (D) are used in telecommunication. However, since radio waves are more commonly used in a wider range of communication systems, including broadcast media and wireless communication devices, the correct answer is (A) radio waves.