The work functions for tungsten and sodium are $4.5 \ eV$ and $2.3 \ eV$ respectively. If the threshold wavelength for sodium is $5460 \ \mathring{A}$,then the threshold wavelength for tungsten is .......... $\mathring{A}$.

Indicate the number of unpaired electrons in:
$(a)$ $P$ $(b)$ $Si$ $(c)$ $Cr$ $(d)$ $Fe$ and $(e)$ $Kr$

What is the condition called when the heart rate decreases below the normal range?

$A$ diatomic gas $\left(\gamma = \frac{7}{5}\right)$ is compressed adiabatically to a volume $\frac{V_i}{32}$,where $V_i$ is its initial volume. The initial temperature of the gas is $T_i$ in Kelvin and the final temperature is $xT_i$. The value of $x$ is:

The number of arrangements of the letters of the word $PALANHAR$ in which no two vowels are together and exactly two vowels are at odd places,is

If $A, B, C, D$ are angles of a cyclic quadrilateral,then $\cos A + \cos B + \cos C + \cos D$ is equal to