Chapter 7, Problem 48Q

Interpretation Introduction

Interpretation:

Energy equivalent of the mass change has to be calculated for the conversion of $4.00g$ hydrogen to helium.

Concept Introduction:

The energy production in sun is through nuclear fusion reaction. That is fusion of 4 hydrogen atoms to give 1 helium atom. The mass number of the newly formed helium nuclei will be slightly less than the mass of 4 hydrogen nuclei. This difference in mass is called mass defect. This loss in mass will be converted as energy and that is how energy is produced in sun. Einstein developed an equation to calculate the energy equivalence for the mass loss and is given as follows,

$\Delta \text{E = }\Delta {\text{m c}}^2$

Where,

    $\Delta \text{E }$ = energy equivalence

  $\Delta \text{m}$ = mass defect

  $\text{c}$    = speed of light = $3.00\times {\text{10}}^8\text{m/s}$

Unit of mass and speed should be taken in SI unit in order to convert energy in terms of joule.

$\text{1J = 1 }\frac{{\text{kg m}}^{\text{2}}}{{\text{s}}^{\text{2}}}$