16. Two capacitors have an equivalent capacitance of 30 pF, if connected in
parallel, and 7.2 pF, if connected in
series. Find C1 and C2.​

C1 + C2 = 30     parallel connection

C1 * C2 / (C1 + C2) = 7.2  series connection

C1 * C2 = 7.2 * (C1 + C2) = 216

C2 + 216 / C2 = 30    using first equation

C2^2 + 216 = 30 C2

C2^2 - 30 C2 + 216 = 0

C2 = 12 or 18    solving the quadratic

Then C1 = 18 or 12

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.