Question

Which of the following statement(s) is/are correct?
I. Radio waves are produced by the accelerated motion of charges in conducting wires.
II. Radio waves are used in radio and television communication systems.
III. Cellular phones use radio waves to transmit voice communication in the ultra high frequency.

• A. I and III
• B. II and III
• C. I and II
• D. All of these

Answer 1

Answer: (D)

Radio waves are produced by the accelerated motion of charges in conducting wires. They are used in radio and television communication systems. They are generally in the frequency range from $500kHz$ to about $1000MHz$. The AM (amplitude modulated) band is from $530kHz$ to $1710kHz$.
Higher frequencies upto $54MHz$ are used for short wave bands. TV waves range from $54MHz$ to $890MHz$.
The FM (frequency modulated) radio band extends from $88MHz$ to $108MHz$. Cellular phones use radio waves to transmit voice communication in the Ultra High Frequency (UHF) band.