Answer:
Pressure is inversely proportional to the volume of gas.
Explanation:
According to Boyle's law,
The volume of given amount of gas is inversely proportional to the pressure applied on gas at constant volume and number of moles of gas.
Mathematical expression:
P ∝ 1/ V
P = K/V
PV = K
when volume is changed from V1 to V2 and pressure from P1 to P2 then expression will be.
P1V1 = K P2V2 = K
P1V1 = P2V2
The mass number is the summation of number of proton and neutron present in a nucleus of an atom. For the neutral atom the number of positive charge (number of proton) must be equal to the number of electrons. The number of electrons present in an atom is the atomic number of the atom. The standard way to express the mass number (a) and atomic number (m) of a atom (say X) is
. Now for silicon number of electron or atomic number is 14. And the mass number (a) given 29. Thus the expression nucleus of silicon will be 
Physical. you didn't burn it or create a chemical reaction