An ideal gas expands isothermally from volume $V_1$ to $V_2$ and is then compressed to the original volume $V_1$ adiabatically. If the initial pressure is $P_1$ and the final pressure is $P_3$,and the total work done is $W$,then:

$A$ small source of sound vibrating at a frequency $500 ~Hz$ is rotated along a circle of radius $\frac{100}{\pi} ~cm$ at a constant angular speed of $5 ~revolutions ~per ~second$. The minimum and maximum frequency of the sound observed by a listener situated in the plane of the circle is (speed of sound is $332 ~ms^{-1}$).

$A$ circle passes through the point $(3, 4)$ and cuts the circle $x^2 + y^2 = a^2$ orthogonally. The locus of its centre is a straight line. If the distance of this straight line from the origin is $25$,then $a^2$ is equal to

The area (in sq. units) of the triangle formed by the tangent and the normal at the point $\left(\frac{a}{\sqrt{2}}, \frac{b}{\sqrt{2}}\right)$ to the curve $\frac{x^2}{a^2}+\frac{y^2}{b^2}=1$ and the $X$-axis is

The function of leghaemoglobin in the root nodules of legumes is

The molar heat capacity of water at constant pressure is $75 \ J \ K^{-1} \ mol^{-1}$. When $1.0 \ kJ$ of heat is supplied to $100 \ g$ of water which is free to expand,the increase in temperature of water is ............. $K$.