MCQ
The dimensions of $\frac{m e^4}{8 \varepsilon_0^2 h^3 c}$ is __________ .
- A$M ^0 L^0 T^0$
- ✓$M ^0 L^{-1} T^0$
- C$M ^0 L^1 T^0$
- D$M ^{-1} L^0 T^0$
✓
Answer
Correct option: B.
$M ^0 L^{-1} T^0$
B
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
A 10 metre wire kept in east-west falling with velocity 5 m/sec perpendicular to the field 0.3 
. The induced e.m.f. across the terminal will be
|
(a) 0.15 V |
(b) 1.5 mV |
(c) 1.5 V |
(d) 15.0 V |
How does the potential difference change with the effect of the dielectric when the battery is kept disconnected from the capacitor?
An electron (mass m) with an initial velocity $\text{v}=\text{v}_0\hat{\text{i}}$ is in an electric field $\text{E}=\text{E}_0\hat{\text{j}}$. If $\lambda_0=\frac{\text{h}}{\text{mv}_0}$, it’s de Breoglie wavelength at time t is given by:
→Assertion : A potentiometer of longer length is used for accurate measurement.
Reason : The potential gradient for a potentiometer of longer length with a given source of e.m.f. becomes small.
|
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
|
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
|
(c) If assertion is true but reason is false. |
|
(d) If the assertion and reason both are false. |
Two coherent sources S1 and S2 are separated by a distance four times the wavelength l of the source. The sources lie along y axis whereas a detector moves along + x axis. Leaving the origin and far off points the number of points where maxima are observed is
|
(a) 2 |
(b) 3 |
(c) 4 |
(d) 5 |
A semiconductor device is connected in a series circuit with a battery and a resistance. A current is found to pass through the circuit. If the polarity of the battery is reversed, the current drops almost to zero. The device may be
| (a) A P-type semiconductor | (b) An N-type semiconductor |
| (c) A PN-junction | (d) An intrinsic semiconductor |
In a p-n junction with open ends:
- There is no systematic motion of charge carriers.
- Holes and conduction electrons systematically go from the p-side to the n-side and from the n side to the p-side respectively.
- There is no net charge transfer between the two sides.
- There is a constant electric field near the junction.
Number of electrons in one coulomb of charge will be
|
(a) 5.46 |
(b) 6.25 |
(c) 1.6 |
(d) 9 |
A parallel combination of two resistors, of 1W each, is connected in series with a 1.5 W resistor. The total combination is connected across a 10 V battery. The current flowing in the circuit is
|
(a) 5 A |
(b) 20 A |
(c) 0.2 A |
(d) 0.4 A |
The forbidden energy gap for germanium crystal at 0 K is: