The products formed when heavy water is reacted with magnesium nitride are:

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

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 length of a pendulum is measured as $1.01 \ m$ and the time for $30$ oscillations is measured as $1 \ \text{minute} \ 3 \ s$. The error in length is $0.01 \ m$ and the error in time is $3 \ s$. The percentage error in the measurement of acceleration due to gravity is:

$ICBN$ stands for

The structure of $PCC$ is