Which of the following species has the highest electron affinity?

An urn $A$ contains $3$ white and $5$ black balls. Another urn $B$ contains $6$ white and $8$ black balls. $A$ ball is picked from $A$ at random and then transferred to $B$. Then,a ball is picked at random from $B$. The probability that it is a white ball is

If three points $A, B$ and $C$ have position vectors $(1, x, 3)$,$(3, 4, 7)$ and $(y, -2, -5)$ respectively and if they are collinear,then $(x, y) = $

Nitrobenzene on reduction using zinc in alkaline medium results in $X$. The number of $\sigma$ and $\pi$ bonds in $X$ is

$A$ long straight rod of diameter $4 \ mm$ carries a steady current '$i$'. The current is uniformly distributed across its cross-section. The ratio of the magnetic fields at distances $1 \ mm$ and $4 \ mm$ from the axis of the rod is

Which of the following characters are related with Poaceae family?
$(a)$ Basal placentation
$(b)$ Feathery stigma
$(c)$ Cypsela fruit
$(d)$ Pentamerous flower