Consider the sun and earth as a single system. how does the law of conservation of energy apply to this system? a) the energy from the sun that reaches earth is destroyed by earth. b) the energy from the sun does not affect the balance of energy on earth. c) the sun creates energy, which subsequently reaches earth and adds to earth’s total energy. d) all the energy that reaches earth from the sun was originally contained within the sun’s atoms.

Before coming into a conclusion, first we have to understand Einstein's mass energy equivalence theory.

As per this theory ,mass and energy are inter convertible.This theory is mathematically written as-

E=mc^2. Where m is the mass and c is the velocity.

So, when some amount of mass is lost, equivalent amount of energy is produced as per this theory.

As per law of conservation of energy, the total energy of the universe is always constant.Energy is neither created nor destroyed.It only changes from one form to another.

In case of sun,the energy is produced due to fusion reaction.In this type of reaction there will be mass defect .Due to this loss of mass, equivalent amount of energy is produced which comes into earth in the form of radiations.

Here the law of conservation of energy is not violated .Before the fusion reaction,the energy was trapped inside the atoms .When the reaction was initiated, correspondingly same amount of energy is produced due to mass defect ,but the total energy is always constant.

Hence,it is also in accordance with the law of conservation of energy.

Hence,the correct answer to the question is D i.e all the energy that reaches Earth from the Sun was originally contained within the Sun’s atoms.