Sketch a sinusoidal wave with an amplitude of 4 cm and a wavelength of 8 cm. This wave represents the electric field portion of a visible EM wave traveling to the right with intensity I0. Sketch an identical wave beneath the first. Sketch another wave of amplitude 6 cm 180° out of phase with the first two. Finally, sketch a fourth wave of amplitude 2 cm in phase with the first two waves. Use the sketches to aid answering the following questions.
(a) What is the amplitude of the sum of these waves?
(b) What is the intensity for the four waves together? (Use any variable or symbol stated above as necessary.)
(c) Consider the case for the first three waves in phase and the fourth wave 180° out of phase. What is the amplitude for the sum of these waves?
(d) What is the intensity of the wave? (Use any variable or symbol stated above as necessary.)