The current $I$ in the circuit will be:

Bamboo and grasses elongate by the activity of ......

In which of the following combinations is buffer action expected?
$A$. $NH_4OH + NH_4Cl$
$B$. $HCl + NaCl$
$C$. $NH_4OH + HCl$ in $2 : 1$ mole ratio
Select the correct answer using the code given below:

Water from a tap emerges vertically downwards with initial velocity $4 ~m/s$. The cross-sectional area of the tap is $A$. The flow is steady and pressure is constant throughout the stream of water. The distance $h$ vertically below the tap, where the cross-sectional area of the stream becomes $\frac{2}{3} A$, is $(g=10 ~m/s^2)$ (in $~m$)

The more commonly used baking powder contains about $30 \% NaHCO_3, 20 \% NaAl(SO_4)_2, 10 \% Ca(H_2PO_4)_2$ and $40 \% $ starch. Which of the following statements is/are correct?

$A$ polygon has $54$ diagonals. Then,the number of its sides is