The resolving limit of a healthy human eye is about:

From which plant were haploid plants first obtained through anther culture?

${ }^{234}Th_{90}$ gets converted to ${ }^{206}Pb_{82}$ through a series of radioactive decay processes. The number of alpha and beta particles lost in this transformation respectively,are

Which of the following reactions occurs at the cathode during the charging of a lead storage battery?

The number of divisors of $7!$ is

Drops of liquid of density $d$ are floating half immersed in a liquid of density $\rho$. If the surface tension of the liquid is $T$,then the radius of the drop is