Advertisements
Advertisements
प्रश्न
Name the type of waves that are used for sound ranging. Why are radio waves not audible to us?
उत्तर
Radio waves. These waves are not audible to us because their frequency is 3 × 104 Hz to 3 × 109 Hz. Which is more than the audible range.
APPEARS IN
संबंधित प्रश्न
The human ear can detect continuous sounds in the frequency range from 20 Hz to 20,000 Hz. Assuming that the speed of sound in air is 330 ms1 for all frequencies; calculate the wavelengths corresponding to the given extreme frequencies of the audible range
A wave passes from one medium to another medium. Mention one property of the wave out of speed, frequency or wavelength which changes.
Explain how is the principle of echo used by
(a) The bat during its flight at night,
(b) The dolphin to locate small fish as its prey.
A type of electromagnetic wave has a wavelength of 50 Å. Name the wave and state one use of this type of wave.
Draw a diagram representing a wave of amplitude 4 cm and wavelength 2 m. If the frequency of the wave is 150 Hz, calculate its velocity.
A radio signal, sent towards the surface of the moon, is received in 2.5 seconds. If the speed of the radio waves is 3 × 108 ms−1, find the distance of the moon from the earth.
Explain reflection at the boundary of a rarer medium.
Explain Reflection at curved surfaces.
Match the following:
| 1. | Stethoscope | a. | Repeated reflections |
| 2. | Echogram | b. | Multiple reflections |
| 3. | SONAR | c. | Ultrasonic waves |
| 4. | Reverberation | d. | Speed of underwater objects |
