The frequency of a light beam "A" is half of that of light beam "B". The ratio EA/Ea of photons energies is:(hint: where EA & Es are the respective energies of light Beam "A" & "B")

Explanation

The correct answer is 1/2. The energy of a photon can be calculated using the formula E = hf, where E is energy, h is Planck's constant, and f is frequency. If the frequency of light beam 'A' is half that of light beam 'B' (i.e., fA = 1/2 * fB), we can express the energies of the two beams as EA = h * fA and EB = h * fB. Substituting for fA gives us EA = h * (1/2 * fB) = (1/2) * h * fB = (1/2) * EB. Thus, the ratio EA/EB = (1/2) and is equal to 1/2. The other options are incorrect for the following reasons: - 1/4: This implies a larger difference in energy than the frequency relationship allows. - 1: This suggests equal energies, which contradicts the stated frequency relationship. - 2: This incorrectly suggests that beam 'A' has higher energy, which is not possible given its lower frequency.