5. [-/1 Points] DETAILS OSCOLPHYS2016 24.3.WA.016. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Citizen's band (CB) radio utilizes frequencies between commercial AM and FM. What is the frequency of an 11.17 m wavelength CB channel? MHz Additional Materials Reading6. [-/1 Points] DETAILS OSCOLPHYS2016 24.4.WA.034.TUTORIAL. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER The helium-neon lasers most commonly used in student physics laboratories have average power outputs of 0.250 mW. (a) If such a laser beam is projected onto a circular spot 3.66 mm in diameter, what is its intensity? w/m2 (b) Find the peak electric field strength. V/m (c) Find the peak magnetic field strength. T Additional Materials Reading Tutorial7. [-/1 Points] DETAILS OSCOLPHYS2016 24.3.WA.025.TUTORIAL. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER An oscillating dipole antenna 1.98 m long with a maximum 39.5 mV potential creates a 500 Hz electromagnetic wave. (a) What is the maximum electric field strength created? V/m (b) What is the corresponding maximum magnetic field strength in the electromagnetic wave? T (c) What is the wavelength of the electromagnetic wave? m Additional Materials Reading Tutorial8. [-/1 Points] DETAILS OSCOLPHYS2016 24.3.WA.026. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A housing attached to a microprocessor uses radiator fins to get rid of excess heat. If the largest amount of radiation emitted by the fins has a frequency of 242.45 THz, what is the associated wavelength? m Additional Materials Reading2. [-/1 Points] DETAILS OSCOLPHYS2016 24.3.WA.028. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER During the Cold War, American submarines operated as "lone wolves" at extreme ocean depths for many months at a time. Ordinary radio signals are greatly attenuated at such depths, making communication with the submarines difficult. One way suggested to communicate with the submarines was a program the Navy called Seafarer that used extremely low frequency waves. If the Seafarer transmitter broadcast at 83 Hz, what would the transmitter's quarter wavelength antenna have to be in order to receive the signal? km Additional Materials Reading3. [-/1 Points] DETAILS OSCOLPHYS2016 24.4.WA.047. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER You and your friend Bruce are experimenting with a red lamp shade and blue lamp shade. You place lamp shades individually over a 120-W light bulb. Assume that the light radiates from the lamps uniformly and 9.8% of their power is converted to light. (a) What is the average intensity of the light at 1.9 m from the red (1 = 710 nm) lamp shade? w/m2 (b) Is the average intensity of the blue (1 = 480 nm) lamp shade at 1.2 m greater than, less than, or equal to the intensity calculated in part (a)? O greater than O less than O equal to Additional Materials Reading4. [-/1 Points] DETAILS OSCOLPHYS2016 24.4.WA.048.TUTORIAL. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Solar cells generate a potential difference when exposed to sunlight. In an experiment, you wish to charge a rechargeable battery by connecting it in series to an array of solar cells. You perform the experiment outdoors, in direct sunlight, when the intensity of solar radiation is 1000 W/m. However, your solar cells only have an efficiency of 13% (that is, only 13% of the sunlight power transmitted to the solar cells is delivered to the rechargeable battery). While the circuit is connected, you measure at one instant the potential difference across the battery to be 4.75 V and the current in the circuit to be 0.21 A. What is the area of the array of solar cells? m2 Additional Materials Reading Tutorial5. [-/1 Points] DETAILS OSCOLPHYS2016 24.3.WA.031. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A pulsar is a type of rotating neutron star that emits a beam of electromagnetic radiation. Imagine a pulsar that is moving toward Earth at a speed of 755.000 km/s. It emits mostly radio waves with a wavelength (at the source) of 121.500 cm. What is the observed wavelength of this radiation on Earth? (Assume the Earth is stationary. Consider the speed of light c = 3.00000 x 10 m/s. Give your answer to at least six significant figures.) 4.0 cm Additional Materials Reading6. [-/1 Points] DETAILS OSCOLPHYS2016 24.3.WA.032.TUTORIAL. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER Astronomers determine that a particular star in our galaxy is moving toward Earth at a speed of 716.0 km/s with respect to the Earth. If Earth receives a wavelength 1 = 680.1 nm from this star, what was the wavelength emitted by the star? nm Additional Materials Reading Tutorial9. [-/1 Points] DETAILS OSCOLPHYS2016 24.1.WA.004. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER An enormous thunderstorm covers Dallas-Ft. Worth. Your best friend Clark is a storm chaser and heads to the center of the storm to take some readings while you stay dry at home. While Clark is at the center of the storm, he sees and hears lightning strike a tree that is 153 m from where he is standing. You are 140 km from the tree. How long does it take for the sound to reach Clark? Assume the speed of sound is 343 m/s. How long does it take for the light to reach you? Will your storm-chaser friend Clark hear the lightning or will you see the lightning first? O Clark hears it first. O You see it first. Additional Materials Reading