Photon A has 2 times the frequency of photon B. How do the energies of the two photons compare?

Question

Photon A has 2 times the frequency of photon B. How do the energies of the two photons compare?

1. A has 4 times the energy of B.

2. A has 1 / 4 times the energy of B.

3. A has 1 / 2 times the energy of B.

4. A has 2 times the energy of B.

Answer 1

Energy = Plancks Constant x Frequency

(it's not h bar - as that is Planck's Constant / 2 * pi) - which is commonly used in Quantum Mechanics

If you double the frequency, it should be obvious that you double the energy.

So it's Answer 4 from the Doctor ;o)

Answer 2

Using Planck’s equation,
E = hv,
The Energy (E) of a photon of light is equal to its frequency (v) multiplied by Planck’s constant (h).

Planck’s constant is a constant (and equal to 6.63 E-34 J s), so it will not change based on the photon.
If one photon has twice the frequency of another photon, it should have twice the energy.

For example, lets say that photon B has a frequency of v, which would mean that photon A would have a frequency of 2 * v, which we will call 2v.
Plugging these frequencies into the above equation for energy,
The energy of photon B = h * v = hv
The energy of photon A = h * 2v = h * 2 * v = 2 * hv

Energy of photon B = hv
Energy of photon A = 2 * hv

So photon A has twice the energy of photon B due to the fact that it has twice the frequency.
So the correct answer is choice “4.”

Answer 3

Here's a hint. Energy of a photon = hbar * frequency. Just frequency, not frequency squared.

Answer 4

I will give you a hint: A photons energy and frequency are propotional.

Answer 5

e=hf, where f = frequency, h = plank's constant, and e = energy. If frequency doubles, energy doubles. Answer is 4.