I believe the correct answer would be "A" energy source.
Answer:
Average velocity of water flow through the pipe = 3.98 m/s
Explanation:
Diameter of pipe = 20 mm
Discharge = 75 L/min
We know that
Discharge = Area x Velocity

Discharge = 75 L/min

Substituting

Average velocity of water flow through the pipe = 3.98 m/s
Its 1.0*10^-7M its considered a concentration because hydrogen ion is exactly equal to hydroxide ions produced by dissociation of water
In an electric circuit, the free electrons are moving around. Since equal charges repel and opposite charges attract, the electrons move from the negatively charged to the positively charged pole of the voltage source.
Electromagnetic radiation