Here are three stress v strain graphs shown on approximately the same scale. Stress B A С Strain a) Match each graph to one of either copper, glass or rubber. Give a reason for each of your choices, perhaps making reference to the grey circular points. b) Explain with the aid of a stress v strain graph why an elastic band becomes warm after stressing and being allowed to return to its original length. c Explain how the Young's modulus for rubber describes the shape of its graph. W

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.

fgravity=10x10=100n case 1

fgravity=30x20=600n case 2

6 times more