An electron of mass m with an initial velocity $$\vec v= v_0\hat i$$$\stackrel{}{}$$$( v_o > 0 )$$ enters in an electric field $$\vec E = -E_0 \hat i$$$$(E_0 = \text{constant}>0)$$ at $$t=0$$. If $$\lambda_0$$${\mathrm{}}_{}$$$\lambda_0$$, is its de-Broglie wavelength initially, then what will be its de-Broglie wavelength at time $$t$$?
1. $$\frac{\lambda_0}{\left(1+ \frac{eE_0}{mv_0}t\right)}$$
2. $$\lambda_0\left(1+ \frac{eE_0}{mv_0}t\right)$$
3. $$\lambda_0 t$$
4. $$\lambda_0$$

Subtopic:  De-broglie Wavelength |
67%
From NCERT
NEET - 2018
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What is the de-Broglie wavelength of a neutron in thermal equilibrium with heavy water at a temperature T (Kelvin) and mass m?

1. $\frac{h}{\sqrt{mkT}}$

2. $\frac{h}{\sqrt{3mkT}}$

3. $\frac{2h}{\sqrt{3mkT}}$ 

4. $\frac{2h}{\sqrt{mkT}}$

Subtopic:  De-broglie Wavelength |
80%
From NCERT
NEET - 2017
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If an electron of mass m with a de-Broglie wavelength of $$\lambda$$ falls on the target in an X-ray tube, the cut-off wavelength ( λ0) of the emitted X-ray will be:

1. ${\lambda }_{0}=\frac{2mc{\lambda }^{2}}{h}$

2. ${\lambda }_{0}=\frac{2h}{mc}$

3. ${\lambda }_{0}=\frac{2{m}^{2}{c}^{2}{\lambda }^{3}}{{h}^{2}}$

4. ${\lambda }_{0}=\lambda$

Subtopic:  De-broglie Wavelength |
From NCERT
NEET - 2016
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An electron of mass m and a photon have the same energy E. Find the ratio of de-Broglie wavelength associated with the electron to that associated with the photon. (c is the velocity of light)

$1.$ ${\left(\frac{E}{2m}\right)}^{1/2}$

$2.$ $c{\left(2mE\right)}^{1/2}$

$3.$ $\frac{1}{c}{\left(\frac{2m}{E}\right)}^{1/2}$

$4.$ $\frac{1}{c}{\left(\frac{E}{2m}\right)}^{1/2}$

Subtopic:  De-broglie Wavelength |
59%
From NCERT
NEET - 2016
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