The number of triangles that can be formed by choosing the vertices from a set of $12$ points,seven of which lie on the same straight line,is

Which of the following crops were introduced into India from the New World?

In a $500 \ mL$ flask,the degree of dissociation of $PCl_5$ at equilibrium is $40 \%$ and the initial amount is $5 \ moles$. The value of equilibrium constant in $mol \ L^{-1}$ for the decomposition of $PCl_5$ is

$Na_2S + Na_2[Fe(CN)_5NO] \longrightarrow Na_4[Fe(CN)_5NOS]$; what are the oxidation numbers of $Fe$ in the reactant complex and the product complex,respectively?

$A$ conducting rod $AC$ of length $4l$ is rotated about a point $O$ in a uniform magnetic field $\vec{B}$ directed into the paper. $AO = l$ and $OC = 3l$. Then:

Two capacitors $C_1 = 2 \, \mu F$ and $C_2 = 4 \, \mu F$ are connected in a circuit as shown in the figure. The potential difference $(V_A - V_B)$ is.....$V$.