Electromagnetic Wave - General Physics - Solved Past Paper, Exams of Physics

Download Electromagnetic Wave - General Physics - Solved Past Paper and more Exams Physics in PDF only on Docsity! 1. (25 pts) a) (5 pts) When the frequency of an electromagnetic wave is increased, what happens to the wave- length? Since the product of wavelength and frequency is constant, if frequency is increased the wavelength must decrease. b) (5 pts) According to Quantum Electro-Dynamics (QED), the current theory of light and electromag- netic radiation, is light a wave or a particle or some hybrid combination of both? According to QED, light is composed of particles called photons. c) (5 pts) Explain the use and/or meaning of the negative sign in Faraday’s Law. The negative sign is called Lenz’s Law. It indicated that the direction of the induced potential opposes the changing magnetic flux. d) (5 pts) If Maxwell didn’t come up with any of the four equations named after him, what was it that he did do to deserve this honor? He combined the four equations to come up with an equation that described electromagnetic radiation as waves that traveled at the speed of light. e) (5 pts) If there are no charges moving in the empty region between the plates of a parallel plate capacitor, what is it that causes a magnetic field to form there when the capacitor is charging? The electric field, and hence the electric flux, between the plates is changing which creates the mag- netic field.