The charge on colloidal particles is due to

If the temperature increases,then what happens to the frequency of the sound produced by the organ pipe?

Oxidation number of $P$ in $Mg_2P_2O_7$ is

$A$ vessel contains $1$ mole of $O_2$ gas (molar mass $32$) at a temperature $T$. The pressure of the gas is $P$. An identical vessel containing $1$ mole of $He$ gas (molar mass $4$) at a temperature $2T$ has a pressure of:

The ratio of the total energy of the $2^{\text{nd}}$ orbit electron for the hydrogen atom $1H^1$ to that of the helium ion $(He^{+})$ $2He^4$ is:

Which of the following is a group of blue-green algae that acts as a biofertilizer?