What is a bacteriophage?

The polar equation $\cos \theta + 7 \sin \theta = \frac{1}{r}$ represents a

If the slope of one line of the pair of lines $2x^2 + hxy + 6y^2 = 0$ is thrice the slope of the other line,then $h =$

What is the mixture of $MgCl_2$ and $MgO$ called?

The dispersive powers of the materials of two lenses forming an achromatic combination are in the ratio of $4: 3$. If the effective focal length of the two lenses is $+60 ~cm$,then the focal lengths of the lenses should be:

Two electrons occupying the same orbital are distinguished by