Which one of the following pairs of gases are the major cause of 'Greenhouse effect'?

Which pair of oxyacids of phosphorus contains $P-H$ bonds?

Three perfect gases at absolute temperatures $T_1, T_2$ and $T_3$ are mixed. The masses of molecules are $m_1, m_2$ and $m_3$ and the number of molecules are $n_1, n_2$ and $n_3$ respectively. Assuming no loss of energy,the final temperature of the mixture is

The inverse of the proposition $(p \wedge \sim q) \Rightarrow r$ is

If $x \log x \frac{dy}{dx} + y = \log x^2$ and $y(e) = 0$, then $y(e^2) = $

The height at which the weight of a body becomes $1/16^{th}$ of its weight on the surface of the earth (radius $R$) is: (in $R$)