The loss in a cable is usually defined in decibels per kilometer (dB/km). If the signal at the beginning of a cable with -0.3 dB /km has a power of 2 mW, what is the power of the signal at 5 km?

A point source emits sound waves with a power oulput of 288 watts. What is the sound level (in dB) at a distance of 69.7 m? (Answer in 2 decimal places)

according to the barometric measurements, the sound has a decibel level of 180 dB at a distance of 161 km. Assuming the intensity falls off as the inverse of the distance squared, what was the decibel level on the island 4800 km away?

An interface is formed between a block of aluminium (with an acoustic impedance of 1.8 x 107 kg m2 s') and a block of copper (with an acoustic impedance of 4.6 x 107 kg m-2 s-1). Longitudinal sound waves travelling through the aluminium are normally incident on the boundary, and are partially reflected. a) What is the ratio of the amplitude of the reflected wave to that of the incident wave? Number b) What is the ratio of the amplitude of the transmitted wave to that of the incident wave? Number c) What percentage of the incident power is transmitted? Number d) What percentage of the incident power is reflected? Number % Ouit P Sove Questi