In a multielectron atom, which of the following orbitals described by three quantum numbers will have same energy in absence of electric and magnetic fields?

A. $\mathrm{n}=1, \mathrm{l}=0, \mathrm{~m}_1=0$

B. $\mathrm{n}=2, \mathrm{l}=0, \mathrm{~m}_1=0$

C. $\mathrm{n}=2, \mathrm{I}=1, \mathrm{~m}_1=1$

D. $\mathrm{n}=3, \mathrm{l}=2, \mathrm{~m}_1=1$

E. $\mathrm{n}=3, \mathrm{l}=2, \mathrm{~m}_1=0$

Choose the correct answer from the options given below:

For hydrogen atom, the orbital/s with lowest energy is/are :

(A) $\mathrm{4 s}$

(B) $3 \mathrm{p}_x$

(C) $3 \mathrm{~d}_{x^2-y^2}$

(D) $3 \mathrm{~d}_{z^2}$

(E) $4 \mathrm{p}_z$

Choose the correct answer from the options given below :

Given below are two statements :

Statement (I) : For a given shell, the total number of allowed orbitals is given by $n^2$.

Statement (II) : For any subshell, the spatial orientation of the orbitals is given by $-l$ to $+l$ values including zero.

In the light of the above statements, choose the correct answer from the options given below :

Given below are two statements about X-ray spectra of elements :

Statement (I) : A plot of $\sqrt{v}$ ( $v=$ frequency of X-rays emitted) vs atomic mass is a straight line.

Statement (II) : A plot of $v(\nu=$ frequency of $X$-rays emitted) vs atomic number is a straight line. In the light of the above statements, choose the correct answer from the options given below :