Physics

Dynamometer type wattmeter is used for the measurement of A.C. as well as D.C. power. It consists of a fixed coil forming the current coil whereas the moving coil forms the potential coil.

Since the Force and the duration of time for which it acted are same, the product of force and time will be the same for both. Since Force×time gives change in momentum of a body, and they had 0 momentum initially, their final momenta will be same.

A wave with a large amplitude will be particularly tall, and a wave with a small aptitude will be particularly short. It turns out that the amplitude tells you how much energy is in the wave. A high amplitude wave is a high-energy wave, and a low-amplitude wave is a low-energy wave.

Air pressure has almost no effect on sound speed. It has no effect at all in an ideal gas approximation, because pressure and density both contribute to sound velocity equally, and in an ideal gas the two effects cancel out. In an ideal gas, intermolecular gaps are always taken to be very large, regardless of pressure.

1 Joule (J) is the MKS unit of energy, equal to the force of one Newton acting through one meter. 1 Watt is the power from a current of 1 Ampere flowing through 1 Volt.