The equivalent weight of phosphoric acid $(H_3PO_4)$ in the reaction,$NaOH + H_3PO_4 \to NaH_2PO_4 + H_2O$ is

The characteristics of a molecular probe are:
$I$. Very long molecule
$II$. Double-stranded
$III$. $DNA$ or $RNA$
$IV$. Complementary to a part of desired gene
The correct pair is:

The refracting angle of a prism is $A$ and the refractive index of the material of the prism is $\cot (A / 2)$. The angle of minimum deviation of the prism is

$A$ magnet freely suspended in a vibration magnetometer makes $40$ oscillations per minute at place $A$ and $20$ oscillations per minute at a place $B$. If the horizontal component of earth's magnetic field at $A$ is $36 \times 10^{-6} ~T$,then its value at $B$ is

The utility of a microorganism like $Trichoderma$ $harzianum$ has been proven in which of the following?

The functional kidney of a frog tadpole is: