$Fe$ is made passive by

$A$ particle moving with a uniform acceleration travels $24 \,m$ and $64 \,m$ in the first two consecutive intervals of $4 \,sec$ each. Its initial velocity is............$m/sec$.

The plates of a parallel plate capacitor are charged up to $200 \ V$. $A$ dielectric slab of thickness $4 \ mm$ is inserted between its plates. Then,to maintain the same potential difference between the plates of the capacitor,the distance between the plates is increased by $3.2 \ mm$. The dielectric constant of the dielectric slab is:

Which of the following is $NOT$ a method of vegetative reproduction in Bryophytes?

Two identical balls $A$ and $B$ are released from the positions shown in the figure. They collide elastically on the horizontal portion $MN$. The ratio of the heights attained by $A$ and $B$ after the collision will be: (neglect friction)

Which property of alkaline earth metals increases with their atomic number?