Questions in Current Electricity

Select	Question
	Two wires A and B of same material and same mass have radius $2r$ and $r$. If resistance of wire A is $34\,\Omega$, then resistance of B will be
	Two rods of same material and length have their electric resistance in ratio 1:2. When both rods are dipped in water, the correct statement will be
	$20\mu A$ current flows for 30 seconds in a wire, transfer of charge will be
	$\sigma_1$ and $\sigma_2$ are the electrical conductivities of Ge and Na respectively. If these substances are heated, then
	1.6 mA current is flowing in conducting wire then the number of electrons flowing per second is
	A current Iis passing through a wire having two sections P and Q of uniform diameters $d$ and $d/2$ respectively. If the mean drift velocity of electrons in sections P and Q is denoted by $v_P$ and $v_Q$ respectively, then
	If an electric current is passed through a nerve of a man, then man
	The resistance of a coil is $4.2 \Omega$ at $100^oC$ and the temperature coefficient of resistance of its material is $0.004/^o C$. Its resistance at $0^oC$ is
	Masses of three wires of copper are in the ratio of $1 : 3 : 5$ and their lengths are in the ratio of 5:3:1. The ratio of their electrical resistances are
	Conductivity increases in the order of