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Q. No.
What is the ratio of the speed of an electron in the first orbit of an \(\mathrm{H}\text-\)atom to the speed of light?
1.
\(\dfrac{1}{137}\)
2.
\(137\)
3.
\(\dfrac{1}{83}\)
4.
\(\dfrac{1}{47}\)
Subtopic: Bohr's Model of Atom |
83%
Level 1: 80%+
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In the diagram shown below, two atomic transitions are shown. If \(\lambda_1= 3000~\mathring{A}\) and \(\lambda_2= 6000~\mathring{A},\)
1. \(2000~\mathring{A}\)
2. \(4000~\mathring{A}\)
3. \(4500~\mathring{A}\)
4. \(9000~\mathring{A}\)
Subtopic: Spectral Series |
74%
Level 2: 60%+
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Let \(f_1\) be the maximum frequency of the Lyman series, \(f_2\) be the frequency of the first line of the Lyman series, and \(f_3\) be the frequency of the series limit of the Balmer series, then which of the following is correct?
1. \(f_1-f_2=f_3\)
2. \(f_2-f_1=f_3\)
3. \(f_1+f_2=f_3\)
4. \(2f_1 = f_2 + f_3\)
1. \(f_1-f_2=f_3\)
2. \(f_2-f_1=f_3\)
3. \(f_1+f_2=f_3\)
4. \(2f_1 = f_2 + f_3\)
Subtopic: Spectral Series |
64%
Level 2: 60%+
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If the wavelength of the first line in the Balmer Series of the hydrogen spectrum is \(\lambda,\) then what is the wavelength of the second line in this series?
1. \(\frac{20}{27}\lambda\)
2. \(\frac{27}{20}\lambda\)
3. \(\frac{25}{27}\lambda\)
4. \(\frac{27}{25}\lambda\)
1. \(\frac{20}{27}\lambda\)
2. \(\frac{27}{20}\lambda\)
3. \(\frac{25}{27}\lambda\)
4. \(\frac{27}{25}\lambda\)
Subtopic: Spectral Series |
77%
Level 2: 60%+
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In an atom, if the transition from \(n = 4\) to \(n=3\) gives ultraviolet radiation, then to obtain infrared radiation, the transition should be:
| 1. | \(5\rightarrow 4\) | 2. | \(3\rightarrow 2\) |
| 3. | \(2\rightarrow 1\) | 4. | \(3\rightarrow 1\) |
Subtopic: Spectral Series |
79%
Level 2: 60%+
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Let \(R\) represent the orbital radius of an electron moving in an orbit and \(K\) represent its kinetic energy. Then the quantity \(KR\) varies with principal quantum number \(n\) as:
| 1. |  |
2. |  |
| 3. |  |
4. |  |
Subtopic: Bohr's Model of Atom |
62%
Level 2: 60%+
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In an \(\alpha\text-\)particle scattering experiment, the number of particles scattered per minute in a direction perpendicular to the direction of incident particles is \(40.\) What will be the number of particles scattered at an angle of \(60^{\circ}\) per minute?
| 1. | \(145\) | 2. | \(160\) |
| 3. | \(172\) | 4. | \(157\) |
Subtopic: Various Atomic Models |
70%
Level 2: 60%+
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The de-Broglie wavelength of an electron in the second orbit of a hydrogen atom is equal to:
| 1. | The perimeter of the orbit. |
| 2. | The half of the perimeter of the orbit. |
| 3. | The half of the diameter of the orbit. |
| 4. | The diameter of the orbit. |
Subtopic: Bohr's Model of Atom |
66%
Level 2: 60%+
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What happens when an electron makes a transition from an excited state to the ground state of a hydrogen-like atom or ion?
| 1. | Its kinetic energy increases but potential energy and total energy decrease. |
| 2. | Kinetic energy, potential energy and total energy decrease. |
| 3. | Kinetic energy decreases, potential energy increases but the total energy remains the same. |
| 4. | Kinetic energy and total energy decrease but potential energy increases. |
Subtopic: Bohr's Model of Atom |
76%
Level 2: 60%+
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A hydrogen atom is excited from the ground state to the state of the principal quantum number \(4.\) Then the number of spectral lines observed will be:
1. \(3\)
2. \(6\)
3. \(5\)
4. \(2\)
1. \(3\)
2. \(6\)
3. \(5\)
4. \(2\)
Subtopic: Spectral Series |
87%
Level 1: 80%+
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