The number of possible enantiomeric pairs that can be produced on monochlorination of $2$-methylbutane is

Degenerate electron pressure will not be sufficient to prevent core collapse of a white dwarf if its mass becomes $n$ times the solar mass. The value of $n$ is:

$A$ horizontal straight wire $20\, m$ long extending from east to west is falling with a speed of $5.0\, m/s$,at right angles to the horizontal component of the earth's magnetic field $0.30 \times 10^{-4}\, Wb/m^2$. The instantaneous value of the $e.m.f.$ induced in the wire will be.....$mV$.

Which of the following liquid mixtures shows a positive deviation from Raoult's law?

$A$ satellite of mass $m$ is in a circular orbit of radius $2R_E$ about the Earth. The energy required to transfer it to a circular orbit of radius $4R_E$ is (where $M_E$ and $R_E$ are the mass and radius of the Earth respectively).

$A$ circle of radius $4$,drawn on a chord of the parabola $y^2 = 8x$ as diameter,touches the axis of the parabola. Then,the slope of the chord is