Answer: Trough
Explanation: The point labeled C in the wave diagram above is the TROUGH of the wave motion. The trough of a wave motion identifies or signifies the point of least or minimum Displacement by measuring the downward Displacement of the wave. The point A is the CREST which is the opposite of the trough, signifying the point of maximum or upward Displacement of the wave cycle.
Point B is the wave amplitude which signifies the maximum extent of vibration from the equilibrium position of a wave. The point labeled D refers to the wavength of the wave motion which is the distance between successive crest or troughs of a wave motion.
Strength of induced current increased when strength of magnetic field increases. It will also increase when the number of turns are increased or if the speed of conductor increases
Ans: Beat Frequency = 1.97HzExplanation:
The fundamental frequency on a vibrating string is

<span> -- (A)</span>
<span>here, T=Tension in the string=56.7N,
L=Length of the string=0.66m,
m= mass = 8.3x10^-4kg/m * 0.66m = 5.48x10^-4kg </span>
Plug in the values in Equation (A)
<span>so </span>

<span> = 197.97Hz </span>
<span>the beat frequency is the difference between these two frequencies, therefore:
Beat frequency = 197.97 - 196.0 = 1.97Hz
-i</span>
charge = current x time = 0.5x 20=10Coulombs