07:04University Physics Lectures, Rate of Energy Transfer by Sinusoidal Waves on StringsJose Menchaca306views
Multiple ChoiceA 100 W lightbulb actually emits around only 10 W of light. What is the intensity of the light 1 cm away if the light is emitted perfectly spherically? What is the magnitude of the electric field emitted by the lightbulb? What about the magnetic field?372views2rank
Multiple ChoiceSuppose a certain star has a temperature of 7000 K. At what wavelength will this star emit the most energy?276views
Multiple ChoiceA 50W light bulb emits light uniformly in all directions. What is the electric field amplitude 10cm away from the light bulb?349views
Multiple ChoiceWhat is the average magnitude of the Poynting vector for an electromagnetic wave with magnetic field amplitude equal to 45nT?274views
Multiple ChoiceAt one instant, an electromagnetic wave has a Poynting vector in the positive x direction and a magnetic field in the negative z direction. What is the direction of the electric field?288views
Open QuestionConsider current I passing through a resistor of radius r, length L, and resistance R. b. Determine the strength and direction of the Poynting vector at the surface of the resistor.56views