-- Energy is never created or destroyed.
-- No energy is added to the pendulum during its swing.
-- If we ignore air resistance and friction, then no energy is lost
from the pendulum during its swing.
-- Therefore the total energy of the pendulum must be constant.
-- Any potential energy lost at any point in the swing
must show up as kinetic energy. If it had 484J at the top,
then it'll have 484J at the bottom.
The sum of Potential Energy and Kinetic Energy is called Mechanical Energy
To solve this problem it is necessary to apply the concepts related to the law of Malus.
The light intensity after passing through the first polarizer is given as
Where,
I = Intensity of unpolarized light
The expression for malus law is given as
Where
\theta = Angle between the first and second polarizers
= Intensities of the light after passing through the first and second polarizers respectively.
The intensity of light after passing first polarizer ( Perpendicular to the surface) is
The angle between the first and second polarizers is given by
The expression for Malus law is given by
Therefore the intensity of the light after passing through both the polarizer is
That would be Earth, because astronomical unit is defined as distance between Earth and sun.
Hope this helps.
r3t40