A linearly-polarized electromagnetic (EM) wave has an electric field with amplitude 1000 V/m. You hold a a linear polarizer in front of it and rotate the polarizer so that all of the EM wave is blocked. You then rotate the polarizer 30 degree. What is the amplitude of the electric field of the EM wave that is transmitted through the polarizer? Select one: 250 V/m500 V/m Depends on rotation direction 866 V/m 750 V/m

E1_max = 866 V/m option D

Explanation:

We know that for linearly polarized light, relation between intensity and electric field is given by:

I_avg = (1/2)*c*e0*E_max^2

I_avg = (1/2)*3*10^8*8.854*10^-12*1000^2

I_avg = 1328.1 W/m^2

Now given that light is already polarized, So Using Malus's law, Intensity of light after passing through polarizer will be:

I1 = I_avg*(cosФ  )^2

Ф = 30 deg, So

I1 = 1328.1*(cos 30 deg)^2 = 996.1 W/m^2

Now electric field corresponding to above Intensity will be:

I1 = (1/2)*c*e0*E1_max^2

E1_max = sqrt (2*I1/(c*e0))

E1_max = sqrt (2*996.1/(3*10^8*8.854*10^-12))

E1_max = 866 V/m

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.