The wire of a flash bulb is made of which of the following?

The points whose position vectors are $2i+3j+4k$,$3i+4j+2k$,and $4i+2j+3k$ are the vertices of

The disadvantage of using common names for species is that

Who is known as the father of Indian Bryology?

The quantum number which explains the line spectra observed as doublets in the case of hydrogen and alkali metals and doublets and triplets in the case of alkaline earth metals is

$A$ convex lens has its radii of curvature equal. The focal length of the lens is $f$. If it is divided vertically into two identical plano-convex lenses by cutting it,then the focal length of the plano-convex lens is ($\mu$ = the refractive index of the material of the lens).