Question

Which range of frequency is used in TV transmission?

• A. 30 Hz - 300 Hz
• B. 30 kHz - 300 kHz
• C. 30 MHz - 300 MHz
• D. 30 GHz - 300 GHz

Hint:

Remember the general order of the radio spectrum for communication: AM Radio (kHz), FM Radio \& TV (MHz), and Satellite \& Wi-Fi (GHz). This helps in quickly eliminating incorrect options in questions related to frequency bands.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
TV transmission requires a large bandwidth to carry both video (picture) and audio (sound) information. This necessitates the use of high-frequency carrier waves. The electromagnetic spectrum is divided into bands, and specific ranges are allocated for different communication purposes.
Step 2: Detailed Explanation:
Let's examine the frequency ranges given:
(A) 30 Hz - 300 Hz: This is the Extremely Low Frequency (ELF) range. These frequencies are in the audible range for humans and have very long wavelengths. They are not suitable for carrying the vast amount of information in a TV signal.
(B) 30 kHz - 300 kHz: This is the Low Frequency (LF) band. It is used for applications like AM radio broadcasting and navigation systems. The bandwidth is still insufficient for television.
(C) 30 MHz - 300 MHz: This is the Very High Frequency (VHF) band. This range provides sufficient bandwidth for TV signals and is historically the primary band used for terrestrial television broadcasting (e.g., channels 2-13 in North America).
(D) 30 GHz - 300 GHz: This is the Extremely High Frequency (EHF) band, also known as millimeter waves. This range is used for high-speed microwave data links, radio astronomy, and satellite communication, but not typically for conventional terrestrial TV broadcasting.
In addition to the VHF band, the Ultra High Frequency (UHF) band (300 MHz - 3 GHz) is also used for TV transmission. However, the range given in option (C) is the correct and standard band used for television.
Step 3: Final Answer:
The frequency range corresponding to the Very High Frequency (VHF) band, which is 30 MHz - 300 MHz, is used for TV transmission. Therefore, option (C) is correct.