Easy MCQ +4 / -1 PYQ · JEE Mains 2025

The energy E and momentum p of a moving body of mass m are related by some equation. Given that c represents the speed of light, identify the correct equation

  1. A $\mathrm{E}^2=\mathrm{pc}^2+\mathrm{m}^2 \mathrm{c}^4$
  2. B $\mathrm{E}^2=\mathrm{pc}^2+\mathrm{m}^2 \mathrm{c}^2$
  3. C $\mathrm{E}^2=\mathrm{p}^2 \mathrm{c}^2+\mathrm{m}^2 \mathrm{c}^4$ Correct answer
  4. D $\mathrm{E}^2=\mathrm{p}^2 \mathrm{c}^2+\mathrm{m}^2 \mathrm{c}^2$

Solution

<p>$$\begin{aligned} & {[E]=M^1 L^2 T^{-2}} \\ & {[P c]=M^1 L^1 T^{-1} \cdot L^1 T^{-1}=M^1 L^2 T^{-2}} \\ & {\left[\mathrm{mc}^2\right]=\mathrm{M}^1 L^2 T^{-2}} \\ & E^2=\mathrm{M}^1 \mathrm{~L}^2 \mathrm{~T}^{-2} \\ & E^2=\mathrm{P}^2 \mathrm{c}^2+\mathrm{m}^2 \mathrm{c}^4 \end{aligned}$$</p>

About this question

Subject: Physics · Chapter: Atoms and Nuclei · Topic: Bohr's Model of Hydrogen Atom

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