Asample of an unknown element was studies using photons with energy of 198.2 mj/mole. the kinetic energy of the ejected electrons was determined to be 38.6 mj/mole. what is the binding energy for these electrons?

Binding energy =159.6 MJ/mole

Explanation:

Given that

Photons energy = 198.2 MJ/mole

Kinetic energy of electrons = 38.6 MJ/mole

We know that the relationship between photons energy,kinetic energy of electron and binding energy

Photons energy = Binding energy + Kinetic energy of electrons

So

Binding energy = Photons energy - Kinetic energy of electrons

Now by putting the values

Binding energy =198.2 - 38.6 MJ/mole

Binding energy =159.6 MJ/mole

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.