As they are Alkali metals (group 1), they are extremely reactive in both air and water so must be stored in kerosine to stop them from reacting with the air or water.
The closest answer is
Alpha - mass of 4 and charge of +2; beta - no mass and charge of -1; gamma - no mass and no charge (consists of energy)
It’s not exactly correct because a beta particle has the (small) mass of an electron (also the positron). All other choices are way off, I’d go with this one.
In physics mass-energy equivalence is the principal that anything having mass has an equivalent amount of energy and vise versa.
Answer:
0.2
Explanation:
Horizontal force=100N
Weight of crate=500 N
We have to find the coefficient of kinetic friction.
Normal ,N=Weight=500N
Horizontal force,
Where 
=Horizontal force
N=Normal force
=Coefficient of kinetic friction
Substitute the values in the formula
Hence, the coefficient of kinetic friction =0.2
F - False.
The nucleus of an atom is positively charge.
