MCQ
If radius of Bohr's first orbit is ' $r$ ' then radius of second orbit will be :
- A$\frac{r}{2}$
- B$\sqrt{2} r$
- C$2 r$
- ✓$4 r$
✓
Answer
Correct option: D.
$4 r$
(D) - $4 r$
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
In a vibration magnetometer, the time period of a bar magnet oscillating in horizontal component of earth's magnetic field is 2 sec. When a magnet is brought near and parallel to it, the time period reduces to 1 sec. The ratio H/F of the horizontal component H and the field F due to magnet will be
| (a) 3 | (b) 1/3 |
(c) 
|
(d) 1/
|
Let np and ne be the number of holes and conduction electrons in an intrinsic semiconductor.
→- $\text{n}_\text{p} > \text{n}_\text{e}$
- $\text{n}_\text{p} = \text{n}_\text{e}$
- $\text{n}_\text{p} < \text{n}_\text{e}$
-
$\text{n}_\text{p}\neq\text{n}_\text{e}$
Which of the following conclusion can be drawn from the result $\oint\overline{\text{B}}\cdot\text{d}\overline{\text{A}}=0$
→A concave lens of focal length 20 cm placed in contact with a plane mirror acts as a
|
(a) Convex mirror of focal length 10 cm |
|
(b) Concave mirror of focal length 40 cm |
|
(c) Concave mirror of focal length 60 cm |
|
(d) Concave mirror of focal length 10 cm |
Kilowatt hour is the unit of :
The electron in the beam of a television tube move horizontally from south to north. The vertical component of the earth's magnetic field points down. The electron is deflected towards
|
(a) West |
(b) No deflection |
(c) East |
(d) North to south |
A magnet of magnetic moment M is rotated through 360° in a magnetic field H, the work done will be
| (a) MH | (b) 2MH | (c) 2πMH | (d) Zero |
How is galvanometer converted into a voltmeter?
When a ray of light passes through a medium in which the velocity is low, then the values of its wavelength and frequency are respectively:
A) Line spectra is due to atoms in gaseous state:
B) Band spectra is due to molecules:
B) Band spectra is due to molecules: