According to einstein's theory, the energy of a photon is a. proportional to its wavelength.
b. proportional to its frequency.
c. constant, since the speed of light is a constant.

Einstein's photoelectric equation giving the energy contained in a photon:

E = hf

E = energy of the photon, h = Planck's constant, f = frequency

The energy is proportional to the frequency.

Choice B

in simple terms, the principle states that the buoyancy force on an object is equal to the weight of the fluid displaced by the object, or the density of the fluid multiplied by the submerged volume times the gravitational acceleration, g. this is also known as upthrust.

wavelength divides in half and speed stays the same.