Answer:
Electromagnetic force creates electromagnetic field.
Explanation:
Electromagnetic force acts between charged particles and this force is the combination of all electrical and magnetic forces. On the other hand, the electromagnetic field is detected by the force it exerts on other magnetic particles and moving electric charges. So, electromagnetic field is created by electromagnetic force. Without this force there cannot be any electromagnetic field.
Answer:
the output power of the hearing aid in two significant figures is 3.2 × 10⁻⁸ W
Explanation:
Output power of sound is given as;
P = I*A
where;
I is the sound intensity = 90dB = 1 × 10⁻³ W/m²
A is the area through which the transmits;
since the canal is circular in shape.
Given;
D as diameter = 6.4mm = 0.0064 m
Output power of the hearing aid = (1 × 10⁻³ W/m²)*(3.217 × 10⁻⁵ m²)
= 3.2 × 10⁻⁸ W
Therefore, the output power of the hearing aid in two significant figures is 3.2 × 10⁻⁸ W.
I believe the instrument is called a Chordophone. It is an instrument that produces sound from a vibrating string stretched between two points, the string may be set in motion by bowing, striking, or plucking. It is one of the four major divisions of instruments in the original Hornbostel-Sachs scheme of musical instrument classification