Guys Pls help me with this i dont understand anything :( 1) Approximate of gold = 19230kg/m³ = 19.1000kg/m³

2) I'm looking for the two points of the line mª= dª× Vª
   
3) Represents the straight line, choosing as the reference unit for:
- the abscissas 1000 (1 square of the notebook corresponds to 1000),
- the ordinates 1 (1 square of the notebook corresponds to 1);

So I can represent the points considering them O = (0,0) and
P = (1,19) because 19000= 19.1000

this a false

explanation:

answer: the correct answer is 1.

explanation: there are various process in which a radioactive nuclei decays:

1) alpha decay: in this process, a heavier nuclei decays into lighter nuclei by releasing alpha particle. the mass number is reduced by 4 units.

2) electron capture: in this decay process, a parent nuclei absorbs an electron and gets converted into a neutron. simply, a proton and an electron combines together to form a neutron. mass number does not change in this process.

3) gamma ray emission: it is a decay process in which an unstable nuclei gives excess energy by a spontaneous electromagnetic process. this decay releases . this process does not change the mass number.

4) positron emission: it is a type of decay process, in which a proton gets converted to neutron and an electron neutrino. this is also known as -decay. in this the mass number remains same.

from the above information, we see that only alpha-decay is producing a change in the mass number of the nucleus.