Fusion reaction is initiated with the help of

An oxide of an element is a gas and dissolves in water to give an acidic solution. The element belongs to

Ionisation enthalpies of $Ce$,$Pr$,and $Nd$ are higher than $Th$,$Pa$,and $U$. Why?

Which one of the following is a correct set?

If the angle of intersection at a point where the two circles with radii $5 \ cm$ and $12 \ cm$ intersect is $90^{\circ}$,then the length (in $cm$) of their common chord is

The half-lives of two radioactive nuclides $A$ and $B$ are $1 \ min$ and $2 \ min$ respectively. Equal weights of $A$ and $B$ are taken separately and allowed to disintegrate for $4 \ min$. What will be the ratio of weights of $A$ and $B$ disintegrated?