The principle of controlled chain reaction is used in

Which of the following is used for making optical instruments?

Somatic hybrids are produced by

$A$ primary coil and a secondary coil are placed close to each other. $A$ current, which changes at the rate of $25 \, A$ in a millisecond, is present in the primary coil. If the mutual inductance is $92 \times 10^{-6} \, H$, then the value of the induced emf in the secondary coil is:

Which of the following is the strongest reducing agent?

Which of the following is a class of $Bryophytes$?