Correct option is A
The correct answer is: (1) A and B only
Explanation:
Infrasound refers to low-frequency sound waves (below 20 Hz), which can travel long distances and are used by several animals for communication. Let’s evaluate each statement based on this context:
Statement A: Infrasound signals propagate over several kilometers in deserts.
Correct – Infrasound can travel efficiently in open terrains like deserts due to low vegetation and reduced obstacles, allowing signals to cover large distances.Statement B: Infrasound signals propagate over several kilometers in open oceans.
Correct – Oceans provide an ideal medium for infrasound propagation because water is a dense medium that supports long-distance travel of low-frequency waves. Many marine mammals, like whales, rely on this.Statement C: Infrasound is employed only by mammals for acoustic signaling.
Incorrect – Infrasound use is not restricted to mammals. For example, birds like cassowaries and pigeons are also known to produce infrasound.Statement D: Infrasound signal transmission is prone to scattering and attenuation.
Incorrect – Infrasound waves, due to their long wavelengths, experience minimal scattering and attenuation, which is why they are suited for long-distance communication.
Thus, only A and B are correct.
Information Booster:
Infrasound is typically in the range of 0.001 to 20 Hz.
It can travel hundreds of kilometers in both air (deserts) and water (oceans).
Used by animals like elephants, giraffes, whales, and some bird species.
In deserts, the lack of vegetation and low humidity supports long-range signal transmission.
In oceans, the SOFAR channel helps infrasound signals travel across vast distances.
It plays a role in navigation, mating calls, and alert signals among species.
Infrasound is also used in geophysical monitoring for earthquakes and volcanoes.
