$A$ potential difference of $20 \ kV$ is applied across an $X-ray$ tube. The minimum wavelength of $X-rays$ generated (in $\mathring{A}$) is

The electric field of a plane electromagnetic wave varies with time with an amplitude of $2 \, Vm^{-1}$ propagating along the $z$-axis. The average energy density of the magnetic field (in $J \, m^{-3}$) is:

For a certain organ pipe,three successive resonance frequencies are observed at $425 \, Hz$,$595 \, Hz$,and $765 \, Hz$ respectively. If the speed of sound in air is $340 \, m/s$,then the length of the pipe is .... $m$

The increasing order of magnetic moments of the following complexes is:-
$I. [Fe(CN)_6]^{4-}$
$II. [Fe(CN)_6]^{3-}$
$III. [Cr(NH_3)_6]^{3+}$
$IV. [Ni(H_2O)_4]^{2+}$

$A$ charged particle moves through a magnetic field perpendicular to its direction. Then

Considering only the principal values of inverse functions,the set $A = \{x \geq 0 : \tan^{-1}(2x) + \tan^{-1}(3x) = \frac{\pi}{4}\}$