The mass of product liberated on anode in an electrochemical cell depends on (where $$t$$ is the time period for which the current is passed).

If a current is passed through a spring then the spring will

If in the circuit, power dissipation is $$150W,$$ then $$R$$ is

If in a circular coil $$A$$ of radius $$R,$$ current $$I$$ is flowing and in another coil $$B$$ of radius $$2R$$ a current $$2I$$ is flowing, then the ratio of the magnetic fields $${B_A}$$ and $${B_B}$$, produced by them will be