White vitriol is

If $a \neq 0, b \neq 0, c \neq 0, a \times b = 0$ and $b \times c = 0$, then $a \times c$ is equal to

Which one of the following arrangements represents the correct order of electron gain enthalpy (with negative sign) of the given atomic species?

The number of circles that touch all the three lines $x+y-1=0$,$x-y-1=0$,and $y+1=0$ is

Match the terms given in List-$I$ with the suitable option provided in List-$II$,regarding the experiment to calculate the resistance and figure of merit of a galvanometer using the half-deflection method.

List-$I$	List-$II$
$A$. Figure of merit $(k)$	$P$. in series
$B$. Current sensitivity $(S_I)$	$Q$. to get power loss minimized
$C$. Deflection is made half by using resistance	$R$. in shunt/parallel
$D$. High resistance box connected	$S$. current per unit deflection
	$T$. deflection per unit current

If the lines $x^2+2xy-35y^2-4x+44y-12=0$ and $5x+\lambda y-8=0$ are concurrent,then the value of $\lambda$ is