The radius of a hydrogen shell is 0.53Å. In its first excited state, radius of the shell will be:
1. 2.12 Å
2. 1.06 Å
3. 8.5 Å
4. 4.24 Å

If the energy of the second Bohr orbit of the hydrogen atom is –328 kJ mol^–1, the energy of the fourth Bohr orbit would be:

Which of the following is the correct symbol, when the number of electrons, protons and neutrons in a species are equal to 18, 16 and 16 respectively?

When electromagnetic radiation of wavelength 300 nm falls on the surface of sodium, electrons are emitted with a kinetic energy of 1.68 ×10⁵ J mol^–1. The minimum energy needed to remove an electron from sodium and the maximum wavelength that will cause a photoelectron to be emitted are, respectively:

1. 2.31 × 10⁵ J mol^–1, 517 nm

2. 23.1 × 10⁵ J mol^–1, 517 nm

3. 3.31 × 10⁵ J mol^–1, 417 nm

4. 33.1 × 10⁵ J mol^–1, 417 nm

The energy and the radius of the first orbit of He⁺ are respectively :

1. \(-8.72\times 10^{-18}J\); 0.02645 nm

2. \(8.72\times 10^{-18}J\); 0.02645 nm

3. \(-7.82\times 10^{-18}J\) ; 0.03655 nm

4. \(7.82\times 10^{-18}J\); 0.03655 nm

A ball weighing 10 g is moving with a velocity of 90 ms^–1. If the uncertainty in its velocity is 5 %, then the uncertainty in its position is  X × 10^–33 m. The value of X will be :

[Given : h = 6.63 × 10^–34 Js]

1. 1.17

2. 1.37

3. 1.67

4. 1.97

A 0.66 kg ball is moving with a speed of 100 m/s. The associated wavelength will be:

$(h=6.6\times {10}^{-34}$ $Js)$

1. $6.6\times {10}^{-34}m$

2. $1.0\times {10}^{-35}$ $m$

3. $1.0\times {10}^{-32}m$

4. $6.6\times {10}^{-32}$ $m$

Match types of wave in Column-I with the corresponding frequency in Column-II and mark the appropriate option:

Match the ensuing rules with the corresponding statements:
 

Which of the following is responsible to rule out the existence of definite paths or trajectories of electrons?

1. Pauli's exclusion principle

2. Heisenberg's uncertainty principle

3. Hund's rule of maximum multiplicity

4. Aufbau principle