Pollen grains of a plant,whose $2n = 28$,are cultured to get callus by tissue culture method. What would be the number of chromosomes in the cells of the callus?

If the mass defect of a nuclide is $3.32 \times 10^{-26} \ g$,its binding energy is (in $MeV$)?

The value of $k$ such that the lines $2x - 3y + k = 0$,$3x - 4y - 13 = 0$,and $8x - 11y - 33 = 0$ are concurrent,is

Which one of the following elements on doping with germanium,makes it a $p$-type semiconductor?

The length of an elastic string is $a \, m$ when the longitudinal tension is $4 \, N$ and $b \, m$ when the longitudinal tension is $5 \, N$. The length of the string in metres when the longitudinal tension is $9 \, N$ is

The shortest distance between the lines $\frac{x - 3}{3} = \frac{y - 8}{-1} = \frac{z - 3}{1}$ and $\frac{x + 3}{-3} = \frac{y + 7}{2} = \frac{z - 6}{4}$ is: