(1.a) The surface area being vibrated by the time the sound reaches the listener is 5,026.55 m².
(1.b) The intensity of the sound wave as it reaches the person listening is 0.02 W/m².
(1.c) The relative intensity of the sound as heard by the listener is 103 dB.
(2.a) The speed of sound if the air temperature is 15⁰C is 340.3 m/s.
(2.b) The frequency of the sound heard by the suspect is 614.3 Hz.
<h3>
Surface area being vibrated</h3>
The surface area being vibrated by the time the sound reaches the listener is calculated as follows;
A = 4πr²
A = 4π x (20)²
A = 5,026.55 m²
<h3>Intensity of the sound</h3>
The intensity of the sound is calculated as follows;
I = P/A
I = (100) / (5,026.55)
I = 0.02 W/m²
<h3>Relative intensity of the sound</h3>

<h3>Speed of sound at the given temperature</h3>

<h3>Frequency of the sound</h3>
The frequency of the sound heard is determined by applying Doppler effect.

where;
- -v₀ is velocity of the observer moving away from the source
- -vs is the velocity of the source moving towards the observer
- fs is the source frequency
- fo is the observed frequency
- v is speed of sound


Learn more about intensity of sound here: brainly.com/question/17062836
 
        
             
        
        
        
Answer:
E = hv
Explanation:
- The photoelectric effect is a phenomenon when the electromagnetic waves of a particular wavelength strike on the metal plate like zinc, it ejects the free electrons.
- The ejected electrons have the kinetic energy and this energy is responsible for the electric energy.
- The kinetic energy of the emitted electrons is linked with the frequency of the incident rays.
- If the rays hitting the metal plate is below the minimum required threshold value, the photoelectrons are not ejected.
- The photoelectric equation is given by
                              E = hν - ∅
Where, ∅ is the minimum energy required to remove an electron.
 
        
             
        
        
        
Answer and Explanation:
the electronic devices always have some noises present in the signal
there are some important considerations in optical fiber communications these are.
- the noise which is contributed by transmitter are electronic random noise, low frequency noise
- noise which is contributed by laser are relative intensity noise, mode partition noise, conversion of phase noise to amplitude noise.
- noise contributed by photo detector are quantum shot noise, shot noise from dark current, avalanche multiplication noise.
PRINCIPLE OF POPULATION INVERSION :
The principle of population inversion is defined as for production of high percentage of simulated emission for a laser beam the number of atoms in higher state should be greater than lower energy state
 
        
             
        
        
        
Explanation:
It is given that,
Mass of the soccer ball, m = 0.425 kg
Speed of the ball, u = 15 m/s
Angle with horizontal, 
Time for which the player's foot is in contact with it, 
Part A,
The x component of the soccer ball's change in momentum is given by :



The y component of the soccer ball's change in momentum is given by :



Hence, this is the required solution.
 
        
             
        
        
        
The period of oscillation is T = 2 * pi * sqrt ( ( m2/3 + m1) / k )
<h3>What is period of oscillation?</h3>
This is the time in seconds it takes to complete one oscillation. where an oscillation is a repetitive to and fro motion. period if the inverse of frequency and both are basic when calculation motion in simple harmonic motion.
The period of oscillation is given as T 
T = 2 * pi * sqrt ( m / k )
where 
m = mass on this case mass of the spring will be inclusive to the mass of the block such that we have: 
m1 = mass of the block
m2 = mass pf the spring 
k = force constant of the spring
including the two masses to the period gives
T = 2 * pi * sqrt ( ( m2/3 + m1) / k )
Read more on period of oscillation here: brainly.com/question/22499336
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