Energy Of A Photon

According to Planck's quantum hypothesis, electromagnetic radiation of frequency $\nu$ is emitted and absorbed in discrete packets called photons, each carrying energy $E=h\nu$, where $h=6.6\times 10^{-34}\text{J s}$ is Planck's constant. The energy depends only on the frequency of the light and is completely independent of the intensity, which merely fixes how many photons are present. Substituting the given frequency, $E=6.6\times 10^{-34}\times 6\times 10^{14}=3.96\times 10^{-19}\text{J}$, which equals about $2.48\text{eV}$. The value $2.64\times 10^{-19}\text{J}$ is wrong because it corresponds to a lower frequency of $4\times 10^{14}\text{Hz}$. The value $1.98\times 10^{-19}\text{J}$ wrongly uses half the stated frequency. The value $5.28\times 10^{-19}\text{J}$ overestimates the frequency as $8\times 10^{14}\text{Hz}$. This is the same photon relation introduced in the NCERT chapter on dual nature, underpinning Einstein's explanation of the photoelectric effect. A quick check confirms the answer lies in the visible-light range of a few electron-volts, which is physically reasonable for yellow sodium light.