Which element is estimated by the Carius method?

$P, Q$ and $R$ are long parallel straight wires in air,carrying currents as shown in the figure. The direction of the resultant force on wire $R$ is

$A$ random variable $X$ takes the values $0, 1$ and $2$. If $P(X=1)=P(X=2)$ and $P(X=0)=0.4$,then the mean of the random variable $X$ is

Match the following columns and select the correct option:

$(a)$ Eosinophils	$(i)$ Immune response
$(b)$ Basophils	$(ii)$ Phagocytosis
$(c)$ Neutrophils	$(iii)$ Release histaminase enzyme
$(d)$ Lymphocytes	$(iv)$ Release granules containing histamine

$(a)\quad (b)\quad (c)\quad (d)$

In the Sun,the important source of energy is

If $z=1+i\sqrt{3}$,then $|\operatorname{Arg} z|+|\operatorname{Arg} \bar{z}|$ is equal to