Which of the following is the strongest reducing agent?

What is obtained when one mole of calcium phosphide is reacted with excess water?

For $|x| < \frac{1}{5}$,the coefficient of $x^3$ in the expansion of $\frac{1}{(1-5 x)(1-4 x)}$ is

The number of radial nodes of $3s$ and $2p$ orbitals are respectively

$A$ body is thrown vertically upwards and reaches its maximum height in $t$ seconds. The total time from the time of projection to reach a point at half of its maximum height while returning (in seconds) is:

Which one of the following statements is $NOT$ the property of light?