Question

The Vividh Bharati station of all India radio, Delhi, broadcasts on a frequency of 1,368kHz (kilohertz). Calculate the wavelength of the electromagnetic radiation emitted by the transmitter. Which part of the electromagnetic spectrum does it belong to?
(a) visible region
(b) radio wave region
(c) infrared region
(d) microwave region

Answer 1

Hint: The electromagnetic (EM) spectrum is the range of all types of EM radiation. Radiation is energy that travels and spreads out as it goes – the visible light that comes from a lamp in your house and the radio waves that come from a radio station are two types of electromagnetic radiation. The other types of EM radiation that make up the electromagnetic spectrum are microwaves, infrared, light, ultraviolet rays, X- rays and gamma rays.

Complete step by step answer:
- We have been provided with frequency: $\nu = 1,368kHz$
- Frequency is the number of occurrences of a repeating event per unit of time. It is also referred to as temporal frequency, which emphasizes the contrast to spatial frequency and angular frequency. Frequency is measured in units of hertz (Hz) which is equal to one occurrence of a repeating event per second.
- We need to calculate the wavelength:
Wavelength is the distance between identical points (adjacent crests) in the adjacent cycles of a waveform signal propagated in space or along a wire. In wireless systems, this length is usually specified in meters (m), centimetres (cm) or millimetres (mm).
Frequency and wavelength are related to each other: Frequency and wavelength are inversely proportional to each other.
So, the relation would be: $\lambda = \dfrac{c} {\nu} $,
Where c= speed of light $3 \times {10^8}m/s$,
So, the wavelength will come out to be: $\lambda = \dfrac {{3 \times {{10} ^8}}} {{1368}} = 219m$,
So, from this wavelength we can say that it belongs to a far infrared or radio wave region.

Note: Wavelength can be calculated using the following formula: $wavelength = \dfrac {{wave~velocity}} {{frequency}} $. Wavelength usually is expressed in units of meters. The symbol for wavelength is the Greek lambda λ, so $\lambda = \dfrac{v}{f} $. This value, divided by the given frequency, will give you wavelength.