Order of toxicity among ammonia,urea and uric acid (from lower to higher) is

How many stereoisomers are possible for the following molecule?

$Assertion (A)$: van der Waals' forces are responsible for chemisorption. $Reason (R)$: High temperature is favourable for chemisorption. The correct answer is

The path difference between the two waves $y_1 = a_1 \sin \left( \omega t - \frac{2\pi x}{\lambda} \right)$ and $y_2 = a_2 \cos \left( \omega t - \frac{2\pi x}{\lambda} + \phi \right)$ is

The shortest distance between the lines $r=3i+5j+7k+\lambda(i+2j+k)$ and $r=-i-j-k+\mu(7i-6j+k)$ is

In the given circuit,the readings of voltmeters $V_1$ and $V_2$ are $300 \, V$ each. The readings of voltmeter $V_3$ and ammeter $A$ are respectively: