On a rainy day,a small oil film on water shows brilliant colours. This is due to

If $x=p+q$,$y=p \omega+q \omega^2$,and $z=p \omega^2+q \omega$,where $\omega$ is a complex cube root of unity,then $xyz$ is equal to:

If $\vec{u}, \vec{v},$ and $\vec{w}$ are three non-coplanar vectors,then $(\vec{u} + \vec{v} - \vec{w}) \cdot ((\vec{u} - \vec{v}) \times (\vec{v} - \vec{w})) = \dots$

$A$ long straight wire carrying a current of $30 ~A$ is placed in an external uniform magnetic field of induction $4 \times 10^{-4} ~T$. The magnetic field is acting parallel to the direction of current. The magnitude of the resultant magnetic induction in tesla at a point $2.0 ~cm$ away from the wire is
$\left(\mu_0=4 \pi \times 10^{-7} ~H/m\right)$

Which of the following is less general in characters as compared to genus?

Which ion binds with troponin during muscle contraction?