Target Exam

CUET

Subject

Physics

Chapter

Dual Nature of Radiation and Matter

Question:

A proton and $\alpha$-particle have same kinetic energy. The de-Broglie wavelength ratio $\frac{\lambda_{p}}{\lambda_\alpha}$ is equal to:

Options:

$\frac{m_\alpha}{m_{p}}$

$m_\alpha \times m_{p}$

$\sqrt{\frac{m_\alpha}{m_p}}$

$\sqrt{\frac{m_{p}}{m_\alpha}}$

Correct Answer:

$\sqrt{\frac{m_\alpha}{m_p}}$

Explanation:

The correct answer is Option (3) → $\sqrt{\frac{m_\alpha}{m_p}}$

De-Broglie Wavelength (λ) is -

$λ=\frac{h}{p}$ [p = Momentum of Particle]

$⇒λ=\frac{h}{\sqrt{2mK}}$   $[p=\sqrt{2mK}]$

$⇒λ_p=\frac{h}{\sqrt{2m_pK}},λ_α=\frac{h}{\sqrt{2m_αK}}$

$\frac{λ_p}{λ_α}=\sqrt{\frac{m_α}{m_p}}$