Answer:
Conductors have magnetic fields; insulators do not have magnetic fields. Conductors do not have magnetic fields; insulators do have magnetic fields. ... In a conductor, electric current cannot flow freely; in an insulator, it can flow freely.
The Law of Conservation of Energy
Answer:
The transmitted intensity through all polarizers is 
Explanation:
According to Malu's law the intensity of a polarized light having an initial intensity
is mathematically represented as

Now considering the polarizer(The polarizing disk) the equation above becomes

Where n is the number of polarizers
Substituting
for the initial intensity 3 for the n and 20° for the angle of rotation


It's number three on your worksheet. ;)