Which of the following equation correctly represents the momentum of a photon of energy E
Question Id: PH0000003 Question : Which of the following equation correctly represents the momentum of a photon of energy E? (a) \(\frac{E}{c}\) (b) \(E^{2}c\) (c) \(Ec\) (d) \(Ec^{2}\) Solution : Here, option (a) \(\frac{E}{c}\) is the correct answer. Explanation : Energy carried by a photon having frequency \(\nu\) is \(E=h\nu\) ; Where \(h\) is Plank's constant. \(\Rightarrow E=\frac{hc}{\lambda}\) \(\Rightarrow \lambda=\frac{hc}{E}\) ; Where \(\lambda\) is wavelength and \(c\) is velocity of light. We know the de Broglie wavelength \(\lambda=\frac{h}{p}\) \[\Rightarrow p=\frac{h}{\lambda}\] \(\Rightarrow p=\frac{h}{\frac{hc}{E}}\) ; putting the value of \(\lambda\) \[\Rightarrow p=\frac{hE}{hc}\] \[\Rightarrow p=\frac{E}{c}\] So, this is the equation of momentum of a photon. If you have any problem regarding this please leave a comment 💬 below