4d, 5p, 5f and 6p orbitals are arranged in the order of decreasing energy. The correct option is:

1.	5f > 6p > 4d > 5p	2.	5f > 6p > 5p > 4d
3.	6p > 5f > 5p > 4d	4.	6p > 5f > 4d > 5p

Which of the following series of transitions in the spectrum of hydrogen atoms falls in the visible region?

1. Brackett series

2. Lyman series

3. Balmer series

4. Paschen series

The orientation of an atomic orbital is governed by:

1. azimuthal quantum number

2. spin quantum number

3. magnetic quantum number

4. principal quantum number

If the mass of electron is 9.11×10^-31 kg  and the planck's constant is 6.626 ×10^-34 Js, then the uncertainty involved in the measurement of velocity within a distance of 0.1 Å is:

1. $5.79\times {10}^6$ $m{s}^{-1}$

2. $5.79\times {10}^7$ $m{s}^{-1}$

3. $5.79\times {10}^8$ $m{s}^{-1}$

4. $5.79\times {10}^5$ $m{s}^{-1}$

An element X has the following isotopic composition: 
²⁰⁰X: 90% 
¹⁹⁹X: 8.0% 
²⁰²X: 2.0% 
The weighted average atomic mass of the naturally-occurring element X is closest to:

1. 200 amu
2. 201 amu
3. 202 amu
4. 199 amu

If uncertainty in position and momentum are equal, then the uncertainty in velocity is:

1. $\frac{1}{2\mathrm{m}}\sqrt{\frac{\mathrm{h}}{\mathrm{\pi }}}$

2. $\sqrt{\frac{\mathrm{h}}{2\mathrm{\pi }}}$

3. $\frac{1}{\mathrm{m}}\sqrt{\frac{\mathrm{h}}{\mathrm{\pi }}}$

4. $\sqrt{\frac{\mathrm{h}}{\mathrm{\pi }}}$

The rule used to determine the maximum number of electrons in a subshell of an atom is:

If n = 6, the correct sequence for the filling of electrons will be: 

1. $\mathrm{ns}$ $\stackrel{}{\to }$ $\left(\mathrm{n}-1\right)$ $\mathrm{d}$ $\stackrel{}{\to }$ $\left(\mathrm{n}-2\right)$ $\mathrm{f}$ $\stackrel{}{\to }$ $\mathrm{np}$

2. $\mathrm{ns}$ $-$ $\left(\mathrm{n}-2\right)$ $\mathrm{f}$ $\stackrel{}{\to }$ $\mathrm{np}$ $\stackrel{}{\to }$ $\left(\mathrm{n}-1\right)$ $\mathrm{d}$

3. $\mathrm{ns}$ $-$ $\mathrm{np}$ $\stackrel{}{\to }$ $\left(\mathrm{n}-1\right)\mathrm{d}$ $\stackrel{}{\to }$ $\left(\mathrm{n}-2\right)$ $\mathrm{f}$

4. $\mathrm{ns}$ $\stackrel{}{\to }$ $\left(\mathrm{n}-2\right)$ $\mathrm{f}$ $\stackrel{}{\to }$ $\left(\mathrm{n}-1\right)$ $\mathrm{d}$ $\stackrel{}{\to }$ $\mathrm{np}$

The energies E₁ and E₂ of two radiations are 25 eV and 50 eV respectively. The relation between their wavelengths i.e., ${\mathrm{\lambda }}_1$ and ${\mathrm{\lambda }}_2$ will be:

1.  ${\mathrm{\lambda }}_1=2{\mathrm{\lambda }}_2$

2.  ${\mathrm{\lambda }}_1=4{\mathrm{\lambda }}_2$

3.  ${\mathrm{\lambda }}_1=\frac{1}{2}{\mathrm{\lambda }}_2$

4.  ${\mathrm{\lambda }}_1={\mathrm{\lambda }}_2$