Question

Which of the following units represent the largest amount of energy?
A.Electron-volt
B.Erg
C.Joule
D.Calorie

Answer 1

Hint: Electron volt, erg, joule and calorie all are the units of energy. Convert electron-volt, erg and calorie to joule and find out which of the following has the highest value.

Complete step by step answer:
Convert electron-volt to joule:
$1{\text{ electron - volt}} = 1.6 \times {10^{ - 19}}{\text{ joule}}$
Convert erg to joule:
$1{\text{ erg}} = {10^{ - 7}}{\text{ joule}}$
Convert calorie to joule:
$1{\text{ calorie}} = 4.18{\text{ joule}}$
$1{\text{ joule}} = 1{\text{ joule}}$
Thus, the highest value is $4.18{\text{ joule}}$. Thus, the unit that represents the largest amount of energy is calorie.

So, the correct answer is Option D .

Additional Information:
Some commonly used units of energy are:
Barrel of oil: It is a unit of measuring volume.
Calorie: One calorie equals $4.18{\text{ joules}}$.
Horsepower: It is used to measure power. One watt equals to $746{\text{ watt}}$.
Joule: It is an SI unit of energy and work. One joule equals one newton meter.
Kilowatt-hour: one kilowatt-hour equals one thousand watt hours.
Kilowatt: It is one thousand watt of electricity.
Megajoule: One megajoule equals one million joules.
Megawatt: One megawatt equals one million watts.
Unit of electricity: One unit of electricity equals one kilowatt-hour.
Volt: It is used to measure electric potential or electromotive force.
Watt (Electric): It is the electrical unit of power.
Watt Hour: It is used to measure electrical energy.

Note:
The amount of kinetic energy lost or gained by an accelerating electron at rest when an electric potential difference of one volt is applied to it is known as electron-volt.
The unit of energy equal to ${10^{ - 7}}{\text{ joule}}$ is known as erg.
The unit of energy or work equal to $1{\text{ kg }}{{\text{m}}^2}{\text{ }}{{\text{s}}^{ - 2}}$ is known as joule.
The energy required to raise the temperature of $1{\text{ kilogram}}$ water by ${1^ \circ }{\text{C}}$ is known as calorie.