If $A \cap B = B$,then

Two non-reactive monoatomic ideal gases have their atomic masses in the ratio $2 : 3$. The ratio of their partial pressures,when enclosed in a vessel kept at a constant temperature,is $4 : 3$. The ratio of their densities is :-

$A$ lens having focal length $f$ and aperture of diameter $d$ forms an image of intensity $I$. If the central region of the lens with diameter $\frac{d}{2}$ is covered by black paper,what will be the new focal length and intensity of the image?

$\lim _{x \rightarrow 0} \frac{\sin x \sin ^{-1} x}{x^2}$ is equal to

The area of the region bounded by the curve $y=x^{2}$ and the line $y=16$ is

$A$ body constrained to move along the $y$-axis is subjected to a constant force $\vec{F} = -\hat{i} + 2\hat{j} + 3\hat{k} \, \text{N}$. The work done by this force in moving the body a distance of $4 \, \text{m}$ along the $y$-axis is ............... $\text{J}$.