Question

sute which one of the following is oon ect

(A) Joule Coulomb x Volt

(B) Joule Coulomb Volt

(c) Joule Volt Ampere

(D) Volt Ampere

Answer 1

One ampere is an elementary unit of current II in the SI units. One coulomb is defined as one ampere second – the charge that the current one ampere transfers in one second Q=ItQ=It.

One joule is defined as twice the kinetic energy that one kilogram gets after being accelerated to one meter per second, 2E=mv22E=mv2, so one joule is really defined as kg⋅m2/s2kg⋅m2/s2. The factor of 22 or 1/21/2 comes from integration.

One watt is defined as one joule per second, the power needed to produce one joule of energy as quickly as in one second. So one watt is defined as J/sJ/s.

One volt is defined as the voltage at which one ampere current has the power of one watt. Equivalently (because of the multiplication by tt explained in the first paragraph), one volt is defined as the voltage at which one coulomb of charge gains the energy of one joule. So
1V=1J1C=1J/s1C/s=1W1A
1V=1J1C=1J/s1C/s=1W1A
Here, the seconds cancelled in the numerator and the denominator.

One must choose which units are more elementary and which of them are derived from them. The SI units start with an ampere, kilogram, second, meter and then define one joule, one coulomb out of them etc. One volt is "more derived" than one ampere or one watt and the statement that "one volt is basically one watt over one ampere" is a definition of one volt. This definition is completely independent from the definition of one watt as "one joule per second". The latter is another definition.

If there are KK names of units, one obviously needs KK definitions. Those are basically equivalent to the statements you described as "equivalent" except that you reverted the other one. A more conventional way to talk is to say that "one watt is one joule per second" and "one volt is one watt per ampere". These are just two definitions. But these two statements are equivalent to the two statements you made.