Yeast is used in the production of

Half-life of a radioactive substance is $20 \, min$. The difference between the time when it is $33 \%$ disintegrated and $67 \%$ disintegrated is approximately ......... $min$.

$A$ horizontal force of $10\, N$ is necessary to just hold a block stationary against a wall. The coefficient of friction between the block and the wall is $0.2$. The weight of the block is ........ $N$.

The compound insoluble in acetic acid is

The centroid of the triangle formed by the pair of straight lines $12x^2 - 20xy + 7y^2 = 0$ and the line $2x - 3y + 4 = 0$ is:

$x A_{(s)} \rightleftharpoons y B_{(g)} + z C_{(g)}$. If $\frac{K_c}{K_p} = (RT)^{-2}$,then which is correct?