Question:
Out of a photon and an electron, the equation \(E = Pc\), is valid for
Out of a photon and an electron, the equation \(E = Pc\), is valid for
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The relation $E = Pc$ holds only for massless particles (photons). For massive particles, $E^2 = p^2c^2 + m_0^2c^4$.
Updated On: Apr 20, 2026
- both
- neither
- photon only
- electron only
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The Correct Option is C
Solution and Explanation
Step 1: Understanding the Concept:
The relativistic energy-momentum relation is \(E^2 = (Pc)^2 + (m_0c^2)^2\).
Step 2: Detailed Explanation:
For a photon: rest mass \(m_0 = 0\), so \(E^2 = (Pc)^2 \Rightarrow E = Pc\). For an electron: \(m_0 \neq 0\), so \(E^2 = (Pc)^2 + (m_0c^2)^2 \neq (Pc)^2\), meaning \(E \neq Pc\).
Step 3: Final Answer:
\(E = Pc\) is valid for photon only.
The relativistic energy-momentum relation is \(E^2 = (Pc)^2 + (m_0c^2)^2\).
Step 2: Detailed Explanation:
For a photon: rest mass \(m_0 = 0\), so \(E^2 = (Pc)^2 \Rightarrow E = Pc\). For an electron: \(m_0 \neq 0\), so \(E^2 = (Pc)^2 + (m_0c^2)^2 \neq (Pc)^2\), meaning \(E \neq Pc\).
Step 3: Final Answer:
\(E = Pc\) is valid for photon only.
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