Hemp fibers are obtained from which plant?

In green plants,cell elongation in the internodal regions is caused by which of the following?

During the electrolysis of copper sulphate aqueous solution using copper electrodes,the reaction taking place at the cathode is:

The discovery of the fungicide known as Bordeaux mixture is associated with which of the following diseases?

In a potentiometer experiment,the balancing length with a cell is $240\,cm$. On shunting the cell with a resistance of $2\,\Omega$,the balancing length becomes $120\,cm$. The internal resistance of the cell is ................... $\Omega$.

Three charges $Q$,$+q$,and $+q$ are placed at the vertices of a right-angled isosceles triangle as shown. The net electrostatic potential energy of the configuration is zero if $Q$ is equal to