Which of the following is the simplest amino acid?

Which of the following has the lowest melting point?

The chemical entities present in the thermosphere of the atmosphere are:

$A$ particle of mass $m$ moves with a velocity $v$ along the line $PC$ (as shown in the figure). The angular momentum of the particle about point $O$ is:

The yellow colour solution of $Na_2CrO_4$ changes to orange-red on passing $CO_2$ gas due to the formation of

$A$ gas is allowed to expand in an insulated container against a constant external pressure of $10 \ atm$ from an initial volume $4.2 \ L$ to $5.2 \ L$. The change in internal energy $\Delta E$ of the gas will be $:-$