Answer:
Pi(3.14) radians or 180º degrees
Explanation:
First of all, we need to obtain the wavelength of a wave traveling to the speed of sound and 420 Hz of frequency.
The formula is:
where l = wavelength in meters
With current values:
l = 336 [m/s]/420[1/s] = 0.8 meters
Since a complete cycle (360º or 2pi radians) needs 0.8 meters to complete, 0.4 meters or 40 cm is just half of it, making a 180º degree phase or 3.14 radians.
The wavelength was doubled, and its energy will be increased by 4 times.
looking at the formula
energy 
also, 
hence it is clear from above that energy is directly proportional to the square of the wavelength.
hence, The wavelength was doubled, and its energy will be increased by 4 times.
<h3>
What is Wavelength?</h3>
- The distance over which a periodic wave's shape repeats is known as the wavelength in physics.
- It is a property of both traveling waves and standing waves as well as other spatial wave patterns. It is the distance between two successive corresponding locations of the same phase on the wave, such as two nearby crests, troughs, or zero crossings.
- The spatial frequency is the reciprocal of the wavelength. The Greek letter lambda is frequently used to represent wavelength.
- The term wavelength is occasionally used to describe modulated waves, their sinusoidal envelopes, or waves created by the interference of several sinusoids.
To learn more about wavelength with the given link
brainly.com/question/13533093
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The radio waves travels between the two boxes and they were travelling through air,
- Box B captures, amplifies and demodulates radio waves.
- Box A modulates, amplifies and send out radio waves.
<h3>What are radio waves?</h3>
- Radio waves are the type of radiation from the electromagnetic spectrum.
- The radio waves can be used in communication technologies like computer, phones, radios , etc..
- Radio waves have lower frequencies but longer wavelength.
- These devices will get signal and then it transmit as mechanical waves through sound.
In that way, the radio waves from box A to B through air, the box A will gets the signal, and then modulates, amplifies and then it send out radio waves. Through the air, Box B will captures, amplifies and demodulates radio waves.
Learn more about radio waves,
brainly.com/question/13989450
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Coulomb's law:
F = k×q₁×q₂/r² where k ≈ 9.00×10⁹NC⁻²m²
Given values:
q₁ = +1.0C
q₂ = -1.0C
F = 650N
Substitute the terms in Coulomb's law with our given values. We will have to use the absolute value of q₂ to so the algebra works out. Solve for r:
650 = 9.00×10⁹×1.0×1.0/r²
r = 3721m
Taking significant figures into account:
<h3>r = 3700m</h3>
Answer:
Electric field, 
Explanation:
Given that,
Charge, 
We need to find the magnitude of electric field 17.1 cm (0.171 m) above an isolated charge. Electric field at a point is given by :
So, the electric field is 
. Hence, this is the required solution.
