The $24$ hour (diurnal) rhythm of our body,such as the sleep-wake cycle,is regulated by the hormone:

The common name of $Benzene-1,2-diol$ is

The compound formed when gypsum is dissolved in aqueous ammonium sulphate solution is:

$\cos 36^{\circ} - \cos 72^{\circ}$ is equal to

Which of the following crops were introduced into India from the New World?

$A$ sinusoidal carrier voltage of frequency $1.5 \, MHz$ and amplitude $50 \, V$ is amplitude modulated by a sinusoidal voltage of frequency $10 \, kHz$ producing $50 \% $ modulation. The lower and upper side-band frequencies in $kHz$ are: