Which of the following metals releases hydrogen gas upon reaction with cold and dilute $HNO_3$?

$A$ conducting rod $PQ$ of length $L = 1.0\, m$ is moving with a uniform speed $v = 2\, m/s$ in a uniform magnetic field $B = 4.0\, T$ directed into the paper. $A$ capacitor of capacity $C = 10\, \mu F$ is connected as shown in the figure. Then:

In which of the following compounds does nitrogen exhibit the highest oxidation state?

Two pendulums have time periods $T$ and $5T/4$. They start $SHM$ at the same time from the mean position. After how many oscillations of the smaller pendulum will they be again in the same phase?

The value of ${\log _3}4 \times {\log _4}5 \times {\log _5}6 \times {\log _6}7 \times {\log _7}8 \times {\log _8}9$ is:

In green plants,cell elongation in the internodal regions is caused by which of the following?