AS 7 Waves PDF

Doppler effect of light Electromagnetic spectrum D C Electromagnetic spectrum Waves that are created as a result of vibrations between an electric field and a magnetic field. Magnetic field and electric...

Doppler effect of light Electromagnetic spectrum D C Electromagnetic spectrum Waves that are created as a result of vibrations between an electric field and a magnetic field. Magnetic field and electric field is at right angles. It is transverse wave. Using 3D movies Sun glass Camera Polarisation 1. Only transverse waves can be plane polarised. 2. All types of electromagnetic waves can be plane polarised. 1. Plane polarised 2. Vertical vibrations pass through the slit. The questions What is meaning of polarisation? Why the longitudinal wave can not be polarized? oscillations are in a single Longitudinal waves vibrate direction, which is along the direction of wave perpendicular to the travel, so no matter what the direction of propagation of orientation of the slit, the the wave. waves will be able to get Why the sound wave can not be through. polarized? Sound wave are longitudinal wave. Single and double The magnitude of intensity There is an angle between polarized light and transmission of axis. 𝑎𝑚𝑝𝑙𝑖𝑡𝑢𝑑𝑒 𝑎𝑓𝑡𝑒𝑟 𝑝𝑜𝑙𝑎𝑟𝑖𝑜𝑑 ∶ 𝐴0 𝑐𝑜𝑠𝜃 𝑖𝑛𝑡𝑒𝑛𝑠𝑖𝑡𝑦 𝐼 = 𝑘𝐴2 𝐼0 𝐼 = 𝐴02 (𝐴0𝑐𝑜𝑠𝜃)2 𝐼 = 𝐼0(𝑐𝑜𝑠𝜃)2 Malus’s law The change in intensity against the angle of transmission axis is shown in the graph below Polarized light A polarizer allows a light wave to pass through it if the direction of oscillation of its electric field matches the alignment of the polarizer, and blocks a light wave if the alignment of the polarizer is perpendicular to the direction of oscillation. 1. When the incident light is unpolarized, the intensity (𝐼) of light passing through the polarizer is reduced by a factor of two compared to the intensity (𝐼0) of light entering the polarizer: I0=2I 2. When the incident light is already polarized to begin with, the intensity (𝐼) of light passing through the polarizer is reduced compared to the intensity (𝐼0) of light entering the polarizer according to Malus’s law. B