Calcium hydride on hydrolysis forms

The magnetic field at the centre of a circular current-carrying conductor of radius $r$ is $B_c$. The magnetic field on its axis at a distance $r$ from the centre is $B_a$. The value of $B_c : B_a$ will be

An ideal gas heat engine operates in a Carnot cycle between $227\,^{\circ}C$ and $127\,^{\circ}C$. It absorbs $6\, kcal$ at the higher temperature. The amount of heat (in $kcal$) converted into work is equal to

The common name of $Benzene-1,2-diol$ is

In which of the following is the sporophyte parasitic on the gametophyte?

If $y = mx + c$ is a tangent to the ellipse $\frac{x^2}{9} + \frac{y^2}{4} = 1$,then the value of $c$ is