Water is to be heated from 10°c to 80°c as it flows through a 2-cm-internal-diameter, 7-m-long tube. the tube is equipped with an electric resistance heater, which provides uniform heating throughout the surface of the tube. the outer surface of the heater is well insulated, so that in steady op- eration all the heat generated in the heater is transferred to the water in the tube. if the system is to provide hot water at a rate of 8 l/min, determine the power rating of the resistance heater. also, estimate the inner surface temperature of the pipe at the exit.

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.

well clustered together.

points close on a scatter diagram