Which one of the following is a true peroxide?

Chemiosmotic theory of $ATP$ synthesis in mitochondrion is based on

Haemocoel is found in

For skywave propagation of a $10\, MHz$ signal,what should be the minimum electron density in the ionosphere?

When an $AC$ source of $e.m.f. \ e = E_0 \sin(100t)$ is connected across a circuit,the phase difference between the $e.m.f. \ e$ and the current $i$ in the circuit is observed to be $\frac{\pi}{4}$ as shown in the diagram. If the circuit consists possibly only of $RC$,$RL$,or $LC$ in series,find the relationship between the two elements.

$A$ stone of mass $m$ is tied to a string and is moved in a vertical circle of radius $r$ making $n$ revolutions per minute. The total tension in the string when the stone is at its lowest point is