Although the evidence is weak, there has been concern in recent years over possible health effects from the magnetic fields generated by transmission lines. A typical high-voltage transmission line is 20 m off the ground and carries a current of 200 A.

A. Estimate the magnetic field strength on the ground underneath such a line.
B. What percentage of the earth’s magnetic field does this represent?

A

The magnetic field strength on the ground underneath such a line is

B

The percentage of the earth’s magnetic field does this represent is 4%

Explanation:

 Mathematically the magnetic field can be expressed as follows

 Where is the permeability of free space

           I is the current

            R is the distance

   Generally the magnetic field at the Earth surface is

Hence the percentage of the earth field it represents is

                                %

answer: its c lololo

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.