Question

1. What is Energy

   • The Capacity to do Work
   • Force times Distance
   • The amount of light emitted by the Sun
   • None of the above

2. Which of the following properties applies to energy?

   • In a system it is a quantity that changes with time
   • In a system it is a quantity that is conserved
   • It is measured in horse power
   • It is measured in Watts

3. How does the Earth store the majority of solar energy?

   • In fossil fuels
   • In Land and Oceans
   • In powering life
   • None of the above, it is mostly reflected in space.

4. What is luminosity in Astrophysics?

   • It is a measure of the power emitted in light
   • It is a measure of the energy per unit time emitted in light
   • It is a physical quantity measured in erg/s
   • All of the above

5. How did Kelvin estimate the age of Sun

   • By measuring its mass
   • By estimating the amount of energy emitted and comparing it to available gravitational energy
   • By estimating the amount of energy emitted and comparing it to available nuclear energy
   • By making consideration on erosion.

6. What powers the Sun?

   • Gravitational energy converted into heat
   • Friction of the high density gas
   • The mass loss in the nuclear fusion of 4 Hydrogen Atoms into 1 Helium atom
   • Burning of gas in core of the Sun

7. Why is fusion difficult to obtain?

   • Because protons repel because of their charge
   • Because it requires very high density
   • Because it requires high temperatures
   • All of the above

8. Is nuclear fusion a possible solution to produce clean and cheap energy?

   • T
   • F

Answer 1

Above are the answers of first 4 questions with some explanations.