Question

Which of the following is not a unit of charge?
$A.$ Coulomb
$B.$ ampere-second
$C.$ microcoulomb
$D.$ ampere per second

Answer 1

Hint: Here we will proceed by using the concept of electric charge to find out the standard units of an electric charge to find out which of the following is not the S.I. unit of charge.

Complete step-by-step answer:

(A). The S.I unit of electric charge is coulomb which is a derived S.I unit and is represented by the symbol C. Coulomb, unit of electric charge in the meter-kilogram-second-ampere system, the basis of the S.I system of physical units. coulomb is stated as the quantity of electricity carried in one second by a current of one ampere.

(B). The S.I unit of electric current is ampere and the S.I unit of time is seconds.
The pace of change of electric charge is known as electric current.

Mathematically, it is given by:

$I = \dfrac{q}{t}$
 $q$ is electric charge
$t$ is time taken
After cross multiplying, we get:

$q = I \times t$
$q = $ ampere-seconds

It is clearly seen that the unit of electric charge is ampere-second. Thus, ampere-second is the unit of electric charge.

(C). Microcoulomb – The microcoulomb is a unit to measure electric charge. The microcoulomb is $\dfrac{1}{{1000000}}$ of a coulomb, which is the electric charge equal to one ampere of a current over one second. The microcoulomb is a multiple of the coulomb, which is the S.I. derived S.I. unit for electric charge. In the metric system, “micro” is the prefix for ${10^{ - 6}}$.

(D). Ampere per second – It is not the unit of charge.
Therefore, the correct option is D.

Note: Whenever we come up with this type of question, one should know what electric charge is. Electric charge –It is a physical property of matter in view of which it encounters a force when put in an electromagnetic field.