Among the following compounds,which is planar in shape?

If the best and the worst paper never appear together,then in how many ways can six examination papers be arranged?

$A$ parallel beam of light of wavelength $6000 \, \mathring{A}$ is diffracted by a single slit of width $0.3 \, \text{mm}$. The angular position of the first minima of the diffracted light is:

In a $\triangle ABC$,if $3a = b + c$,then $\cot \frac{B}{2} \cot \frac{C}{2}$ is equal to :

Which of the following statements is not true?

If $R$ is the universal gas constant,the amount of heat needed to raise the temperature of $2\, mol$ of an ideal monoatomic gas from $273\, K$ to $373\, K$ when no work is done is: (in $,R$)