A beam of natural light falls on a system of 5 polaroids which are arr...
A beam of natural light falls on a system of 5 polaroids which are arr...
The given system consists of 5 polaroids arranged in succession, with the transmission axes of each polaroid turned through 60 degrees with respect to the preceding one. We need to determine the fraction of incident light intensity that passes through the system.
Let's analyze the system step by step:
1. **First Polaroid**: When unpolarized light falls on the first polaroid, it allows only the light vibrating in a particular plane to pass through. Since the transmission axis of the first polaroid is arbitrary, it lets half of the incident light intensity to pass through. Therefore, the intensity of light passing through the first polaroid is 1/2.
2. **Second Polaroid**: The light coming out of the first polaroid is now linearly polarized in a particular direction. When it falls on the second polaroid, which is oriented 60 degrees with respect to the first one, only the component of light vibrating in a direction parallel to the transmission axis of the second polaroid will pass through. The projection of the linearly polarized light along the transmission axis of the second polaroid is given by cos^2(60). Hence, the intensity of light passing through the second polaroid is (cos^2(60)) * (1/2) = 1/4.
3. **Third Polaroid**: Similarly, the light coming out of the second polaroid is linearly polarized in a particular direction. When it falls on the third polaroid, which is oriented 60 degrees with respect to the second one, only the component of light vibrating in a direction parallel to the transmission axis of the third polaroid will pass through. The projection of the linearly polarized light along the transmission axis of the third polaroid is again given by cos^2(60). Hence, the intensity of light passing through the third polaroid is (cos^2(60)) * (1/4) = 1/8.
4. **Fourth Polaroid**: The same process repeats for the fourth polaroid, and the intensity of light passing through it is (cos^2(60)) * (1/8) = 1/16.
5. **Fifth Polaroid**: Finally, when the light falls on the fifth polaroid, which is oriented 60 degrees with respect to the fourth one, only the component of light vibrating in a direction parallel to the transmission axis of the fifth polaroid will pass through. The projection of the linearly polarized light along the transmission axis of the fifth polaroid is once again given by cos^2(60). Hence, the intensity of light passing through the fifth polaroid is (cos^2(60)) * (1/16) = 1/32.
Therefore, the fraction of incident light intensity that passes through the system is 1/32.
Hence, the correct answer is option 1) 1/32.