Water on a smooth floor can made you slip, which means water is also a lubricant. can you think of reasons why oil and grease and not water is used i machines as a lubricant?

The boiling of water is 100°, while the boiling point of lubricating oil is anywhere from 370°-600°. So oil is used because if the machine gets too hot, then the water may boil off, which will make the machine lose its lubrication.

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.

explanation:

considering the bohr theory, the type of connection that requires the transfer the answer conuldn't be right