Which of the following groups of cells in the male gonad represents haploid cells?

What is the hybridization state of the central atom in the conjugate base of $NH_4^{+}$ ion?

The degree of ionization of $0.10 \ M$ lactic acid is $4.0 \ \%$. The value of $K_a$ is

The classification of $Monera$ is based on which of the following?

The radiation emitted by a star $A$ is $10000$ times that of the sun. If the surface temperatures of the sun and the star $A$ are $6000 \ K$ and $2000 \ K$ respectively,the ratio of the radii of the star $A$ and the sun is : (in $: 1$)

$A$ galvanometer $G$ deflects full scale when a potential difference of $0.50 \ V$ is applied. The internal resistance of the galvanometer $r_g$ is $25 \ \Omega$. An ammeter is constructed by incorporating the galvanometer and an additional shunt resistance $R_S$. The ammeter deflects full scale when a measurement of $2.0 \ A$ is made. The resistance $R_S$ is closest to ............. $\Omega$.