If radius of second Bohr orbit of the \(He^+\) ion is 105.8 pm, what is the radius of third Bohr orbit of \(Li^{2+}\) ion? 
1. 158.7 Å 2. 158.7 pm 
3. 15.87 pm  4. 1.587 pm

Subtopic:  Hydrogen Spectra |
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Which one of the following electrons in the ground state will have least amount of energy?

1. An electron in hydrogen atom.
2. An electron in 2p orbital of carbon atom.
3. The electron of copper atom present in 4s orbital.
4. The outermost electron in sodium atom.
Subtopic:  AUFBAU Principle |
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A monochromatic infrared range finder of power 1milli watt emits photons with wavelength 1000 nm in 0.1 second. The number of photons emitted in 0.1 second is:
(Given: h = \(6.626 \times 10^{-34} J~s\) , c = \(3 \times 10^8 m~s^{-1}, \) Avogadro number = \(6.022 \times 10^{23}\))

1. \(30 \times 10^{37}\)
2. \(5 \times 10^{14} \)
3. \(30 \times 10^{34} \)
4. \(5 \times 10^{11} \)

Subtopic:  Electromagnetic Radiation |
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Assertion (A): Half-filled and fully-filled degenerate orbitals are more stable.
Reason (R): Extra stability is due to the symmetrical distribution of electrons and high exchange energy.
 
1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. (A) is False but (R) is True.
Subtopic:  Shell & Subshell |
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Assertion (A):  Helium and berylium having the similar outer electronic configuration of type \(ns^2\).
Reason (R):   Both are chemically inert.
 
1. Both (A) and (R) are True and (R) is the correct explanation of (A).
2. Both (A) and (R) are True but (R) is not the correct explanation of (A).
3. (A) is True but (R) is False.
4. Both (A) and (R) are False.

 
Subtopic:  AUFBAU Principle |
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Using the following statements, identify the correct set of statements:
(i). n (principal quantum number) can have values 1, 2, 3, 4, .......
(ii). The number of orbitals for a given value of l is (2l+1).
(iii). The value of spin quantum numbers is always \(\pm\frac12\).
(iv). For l=5, the total number of orbitals is 9.

1.  (i), (ii), (iii)
2.  (i), (ii), (iv)
3.  (i), (ii), (iii), (iv)
4.  (i), (iii), (iv)
Subtopic:  Quantum Numbers & Schrodinger Wave Equation |
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Given below is the probability density graph of an orbital. 

The above graph represents the orbital: 
1. 1s
2. 2s 
3. 2p 
4. 3s
Subtopic:  Quantum Numbers & Schrodinger Wave Equation |
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Match List-I with List-II:
List-I
(quantum number)
List-II
(Orbital)
(A) n = 2, \(\ell\) = 1 (I) 2s
(B) n = 3, \(\ell\) = 2 (II) 3s
(C) n = 3, \(\ell\) = 0 (III) 2p
(D) n = 2, \(\ell\) = 0 (IV) 3d
 
Choose the correct answer from the options given below:
(A) (B) (C) (D)
1. (III) (IV) (I) (II)
2. (IV) (III) (I) (II)
3. (IV) (III) (II) (I)
4. (III) (IV) (II) (I)
Subtopic:  Shell & Subshell |
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When electromagnetic radiation of wavelength 300 nm falls on the surface of a metal, electrons are emitted with the kinetic energy of 1.68 × 105 J mol–1. The minimum energy needed to remove one mole of electron from the metal is: 

(h = 6.626 × 10–34 Js, c = 3 × 108 ms–1, NA = 6.022 × 1023 mol–1)

1.  2.31 × 106 J mol–1
2.  3.84 × 104 J mol–1
3.  3.84 × 10–19 J mol–1
4.  2.31 × 105 J mol–1
Subtopic:  Photo Electric Effect |
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The threshold frequency \((\nu_0)\) for metal is \(6.0 × 10^{14}~\text {sec}^{-1}\). When radiation of frequency, \(\nu = 1.0 × 10^{15}~\text {sec}^{-1} \)  hits the metal, the kinetic energy of the electron emitted is:

[Given: h = 6.62 × 10-34 Js]

1. 3.65 × 10–19 J
2. 2.65 × 10–19 J
3. 1.95 × 10–19 J
4. 2.95 × 10–20 J
Subtopic:  Photo Electric Effect |
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