In the given figure,what do $A$ and $B$ represent respectively?

On combustion of $Li$,$Na$,and $K$ in excess of air,the major oxides formed,respectively,are:

Which among the following factors is the most important in making fluorine the strongest oxidising halogen?

When a big drop of water is formed from $n$ small drops of water,the energy loss is $3E$,where $E$ is the energy of the bigger drop. If $R$ is the radius of the bigger drop and $r$ is the radius of the smaller drop,then the number of smaller drops $(n)$ is:

Which of the following groups of organisms can interbreed?

$A$ police car with a siren of frequency $8 \, kHz$ is moving with uniform velocity $36 \, km/hr$ towards a tall building which reflects the sound waves. The speed of sound in air is $320 \, m/s$. The frequency of the siren heard by the car driver is .... $kHz$.