Electromagnetic Waves and Intensity

What is the relationship between the energy stored in the electric and magnetic fields of an electromagnetic wave?

• All energy is stored in the electric field.

• All energy is stored in the magnetic field.

• Energy is equally divided between electric and magnetic fields.

• Energy is stored only in the magnetic field.

How is the intensity of light from the Sun that reaches Earth defined?

• The power per unit area received on Earth.

• The energy per unit volume received on Earth.

• The total energy emitted by the Sun.

• The total power output of the Sun.

What is the formula for the surface area of a sphere?

• 2 PI R squared

• 4 PI R squared

• PI R squared

• 3 PI R squared

If a planet is three times further from a star than another planet, how does the intensity of starlight compare?

• It is three times less.

• It is nine times less.

• It is the same.

• It is nine times more.

What happens to the intensity of light as the distance from the source increases?

• It remains constant.

• It increases linearly.

• It increases exponentially.

• It decreases inversely with the square of the distance.