The ratio of the wavelengths of the last lines of the Balmer to Lyman series is

1. 4:1 2. 27:5
3. 3:1 4. 9:4

Subtopic:  Hydrogen Spectra |
 74%
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If the electronic structure of oxygen atom is written as 1s2, 2s2  it would violate:

1. Hund's rule.

2. Paulis exclusion principle.

3. Both Hund's and Pauli's principles.

4. None of the above.

Subtopic:  Pauli's Exclusion Principle & Hund's Rule |
 74%
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Assertion (A): Bohr’s orbits are also called stationary states.
Reason (R): Electrons are stationary in an orbit.
 
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:  Bohr's Theory |
 68%
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Assertion (A): In the third energy level, there is no f subshell.
Reason (R): For n = 3, the possible values of l are 0, 1, 2 and for f subshell l = 3.

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 |
 78%
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Assertion (A):  The angular momentum of an electron in an atom is quantized.
Reason (R):  In an atom, only those orbits are permitted in which the angular momentum of the electron is a natural number multiple of h/2π.

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:  Bohr's Theory |
 80%
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Assertion (A): The radius of the second orbit of He+ is equal to that of the first orbit of hydrogen.
Reason (R) The radius of an orbit in hydrogen-like species is directly proportional to n and inversely proportional to Z.

1. Both  (A) and (R) are True and (R) is the correct explanation of the (A).
2. Both (A) and (R) are True and (R) is not the correct explanation of the (A).
3.  (A) is True but (R) is False.
4. Both (A) and (R) are False.
Subtopic:  Bohr's Theory |
 69%
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Assertion (A): The number of radial nodes in 3 dz2  , is zero.
Reason (R): The number of angular nodes of atomic orbitals is equal to the value of l.

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:  Nodal Plane |
 66%
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The velocity associated with a proton moving at a potential difference of 1000 V is 4.37 × 105 ms–1. If the hockey ball of mass 0.1 kg is moving with this velocity, then the wavelength associated with this velocity would be:

1. 1.52 ×10-38 m
2. 2.54 × 10-32 m
3. 1.52 × 10-36 m
4. 3.19 × 10-34 m

Subtopic:  De Broglie Equation |
 66%
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The characteristic velocity associated with a neutron that has a wavelength of 800 pm is :
 

1. 496 m s-1 2. 567 m s-1
3. 494 cm s-1 4. 501 m s-1
Subtopic:  De Broglie Equation |
 51%
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If the velocity of the electron is 1.6 × 106 ms-1. The de Broglie wavelength associated with this electron is:  

1. 590 pm
2. 455 pm
3. 512 pm
4. 401 pm

Subtopic:  De Broglie Equation |
 72%
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