MCQ
An electron is accelerated through a potential difference of $10,000\; \mathrm{V}$. Its de Broglie wavelength is, (nearly):

$\left(\mathrm{m}_{\mathrm{e}}=9 \times 10^{-31}\;\mathrm{kg}\right)$

  • A
    $12.2 \times 10^{-13} \;\mathrm{m}$
  • $12.2 \times 10^{-12} \;\mathrm{m}$
  • C
    $12.2 \times 10^{-14} \;\mathrm{m}$
  • D
    $12.2\; \mathrm{nm}$

Answer

Correct option: B.
$12.2 \times 10^{-12} \;\mathrm{m}$
b
$\lambda=\sqrt{\frac{150}{V}} \mathring A$

$\lambda=\sqrt{\frac{150}{10^{4}}} \mathring A$$=12.27 \times 10^{-12} \;\mathrm{m}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

In $Y.D.S.E.$ seperation between the two slits $S_1\,S_2$ is a and screen is at distance $x$ from the slits. Source of light $S$ is moving with velocity $v$ parallel to $S_1\,S_2$ and is at distance $h$ from $S_1\,S_2$. What is frequency of change in brightness at central point?
A simple pendulum of mass $'m',$ length $'I'$ and charge $'+q'$ suspended in the electric field produced by two conducting parallel plates as shown. The value of deflection of pendulum in equilibrium position will be -
A convex lens makes a real image 4 cm long on a screen. When the lens is shifted to a new position without disturbing the object, we again get a real image on the screen which is 16 cm tall. The length of the object must be
In the hysteresis cycle, the value of H needed to make the intensity of magnetisation zero is called
Potential difference between centre $\&$ the surface of sphere of radius $R$ and uniform volume charge density $\rho$ within it will be :
If an object is placed at $A(OA > f)$; Where f is the focal length of the lens the image is found to be formed at $B.A$ perpendicular is erected at $o$ and $C$ is chosen on it such that the angle $\angle BCA$ is a right angle. Then the value of f will be
When a coil of cross-sectional area A and number of turns $N$ is rotated in a uniform magnetic field $B$ with angular velocity $\omega$ then the maximum emf induced in the coil will be.
The equivalent resistance across $AB$ would be ............ $\Omega$
The capacity of a parallel plate capacitor with no dielectric substance but with a separation of 0.4 cm is 2 μF. The separation is reduced to half and it is filled with a dielectric substance of value 2.8. The final capacity of the capacitor is
In Circuit-$1$ and Circuit- $2$ shown in the figures, $R_1=1 \Omega, R_2=2 \Omega$ and $R_3=3 \Omega$. $P_1$ and $P_2$ are the power dissipations in Circuit-$1$ and Circuit-$2$ when the switches $S_1$ and $S_2$ are in open conditions, respectively. $Q_1$ and $Q_2$ are the power dissipations in Circuit-$1$ and Circuit-$2$ when the switches $S_1$ and $S_2$ are in closed conditions, respectively.

Which of the following statement($s$) is(are) correct?

$(A)$ When a voltage source of $6 V$ is connected across $A$ and $B$ in both circuits, $P_1$

$(B)$ When a constant current source of $2 Amp$ is connected across $A$ and $B$ in both circuits, $P_1>P_2$.

$(C)$ When a voltage source of $6 V$ is connected across $A$ and $B$ in Circuit-$1$, $Q_1>P_1$.

$(D)$ When a constant current source of $2 Amp$ is connected across $A$ and $B$ in both circuits, $Q_2$