Radio waves are
- produced by hot bodies
- in the frequency range 109 Hz to 1012 Hz
- suitable for radar systems
- used in cellular phones to transmit voice communication
- used to kill germs in water purifiers
The Correct Option is D
Approach Solution - 1
Radio waves are electromagnetic waves that have frequencies in the range of \( 10^3 \, \text{Hz} \) to \( 10^{12} \, \text{Hz} \). They are widely used for various communication systems, including AM/FM radio, TV signals, and cellular phones. In cellular phones, radio waves are used to transmit voice communication by modulating the voice signal onto a carrier wave.
Thus, the correct answer is that radio waves are used in cellular phones to transmit voice communication.
The correct option is (D) : used in cellular phones to transmit voice communication
Approach Solution -2
Let's analyze each statement about radio waves:
1. Produced by hot bodies
→ Not typically. Infrared and visible light are more associated with thermal radiation.
2. In the frequency range 109 Hz to 1012 Hz
→ This range corresponds more to microwaves and far-infrared, not radio waves.
Radio waves typically range from 103 Hz to 109 Hz.
3. Suitable for radar systems
→ Yes, radar uses radio waves and microwaves.
4. Used in cellular phones to transmit voice communication
→ Yes, cellular communication often uses radio and microwave frequencies.
5. Used to kill germs in water purifiers
→ Incorrect. UV rays, not radio waves, are used for sterilization.
Correct statements:
✔ Suitable for radar systems
✔ Used in cellular phones to transmit voice communication
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