Which of the following is not the unit of energy?

Options

A. watt
B. joule
C. calorie
D. erg

Answer

A

Explanation

Watt is a measure of the quantity of energy used per unit time (i.e., power) and equals 1 joule per second. The `SI` unit fo energy, kg `m^(2) s^(-2)`, is given the name joule `(J)` (pronounced jewl), after the English scientist James Prescott Juole who studies the energy concept. Joule is an extermely small unit. Calorie (cal) is a non- `SI` unit of energy, commonly used by chemist, originally defined as the amount of energy required to raise the temperature of one gram of water by one degree Celsius. This is only an approximate definition because the energy needed to heat water depends slightly on the temperature of water. Exact definition is `1 cal = 4.184 J`. Erg is a unit of energy (work in the dyne acting through a distance of 1 centimeters `(1 erg = 10^(-7) J)`.
`1 cal gt 1 J gt 1 erg`