Physics 122-03 Test 4: Electromagnetic Waves and Particle Behavior, Exams of Physics

Download Physics 122-03 Test 4: Electromagnetic Waves and Particle Behavior and more Exams Physics in PDF only on Docsity! Name: Physics 122-03 Test 4 1. An electromagnetic wave is described by the fields E = E0 cos(k · x − ωt) B = B0 cos(k · x − ωt) where the amplitude of the electric field is E0 = 3.0×104(V/m) x̂, the magnetic field amplitude B0 is positive along the positive ŷ direction, and the angular frequency ω is equal to 6.0 × 106s−1. (a) (2 pts.) What is the magnitude of B0 (including its units)? (b) (1 pt.) What is the magnitude k of the vector k? (c) (1 pt.) What is the direction of the vector k? (d) (2 pts.) The wave passes through a linear polarizer which fixes the new polarization direction to be 60 degrees away from the old polarization direction. What is the magnitude of the new electric field amplitude? 1 2. Particles of mass m = 6.6 × 10−26 kg are all moving in the x direction with speed v = 0.5 m/s, and the beam of particles passes through two slits in a wall. The slits are a distance d = 0.1 mm apart (in the y direction), and they each have a width a = 0.01 mm (also in the y direction). The particles hit a screen located a distance L = 20.0 m away (in the x direction), forming a pattern on the screen. (a) (2 pts.) What is the DeBroglie wavelength of these particles? (b) (3 pts.) If no measurement is made regarding which slit each particle goes through, how far above the central bright maximum will the first dark minimum be in the pattern? (c) (3 pts.) If the lower slit is covered up, how far above the central bright maximum will the first dark minimum be in the new pattern? 2