Question 2 1. On a data network, Ping measures the round-trip time of messages. Ping at long distance is limited by data transfer at the finite speed of light. Atelecom cable has a length of 30,000 km. The glass fiber has a refractive index of 1.5. Find the minimum Ping in second if data go through thiswhole cable length and come back (round-trip).2. A half wavelantenna has the best reception when its length is half the TV signal wavelength. A UHF TV antenna is 40 cm long. Find the TV signalfrequency in MHz with the best reception.3. A heat sink for computer server absorbs all the

Given value--- length of TV antenna = 40 cm. We have to find--- frequency of signal ?

eign and come back (round-trip). 2. A half wave lantenna has the best reception when its length is half the TV signal wavelength. A UHF TV antenna is 40 cm long. Find the TV signal frequency in MHz with the best reception. uin Ping in second if data go through this

eign and come back (round-trip). 2. A half wave lantenna has the best reception when its length is half the TV signal wavelength. A UHF TV antenna is 40 cm long. Find the TV signal frequency in MHz with the best reception. uin Ping in second if data go through this

University Physics Volume 3

17th Edition

ISBN:9781938168185

Author:William Moebs, Jeff Sanny

Publisher:William Moebs, Jeff Sanny

Chapter4: Diffraction

Section: Chapter Questions

Problem 54P: The 305-m-diameter Arecibo radio telescope pictured in Figure 4.20 detects radio waves with a...

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Radio telescopes are telescopes used for the detection of radio emission from space. Because radio waves have much longer wavelengths than visible light, the diameter of a radio telescope must be very large to provide good resolution. For example, the radio telescope in Penticton, BC in Canada, has a diameter of 26 m and can be operated at frequencies as high as 6.6 GHz. (a) What is the wavelength corresponding to this frequency? (b) What is the angular separation of two radio sources that can be resolved by this telescope? (c) Compare the telescope’s resolution with the angular size of the moon.
Figure 24.26 shows the interference pattern of two radio antennas broadcasting the same signal. Explain how this is analogous to the interference pattern for sound produced by two speakers. Could this he used to make a directional antenna system that broadcasts preferentially in certain directions? Explain. Figure 24.26 An overhead view of two radio broadcast antennas sending the same signal, and the interference pattern they produce.
Figure P24.69 shows a radio-wave transmitter and a receiver, both h = 50.0 m above the ground and d = 6.00 102 m apart. The receiver can receive signals directly from the transmitter and indirectly from signals that bounce off the ground. If the ground is level between the transmitter and receiver and a /2 phase shift occurs upon reflection, determine the longest wavelengths that interior (a) constructively and (b) destructively. Figure P24.69
To save money on making military aircraft invisible to radar, an inventor decides to coat them with a nonreflective material having an index of refraction of 1.20, which is between that of air and the surface of the plane. This, he reasons, should be much cheaper than designing Stealth bombers. (a) What thickness should the coating be to inhibit the reflection of 4.00-cm wavelength radar? (b) What is unreasonable about this result? (c) Which assumptions are unreasonable or inconsistent?
Two radio antennas separated by d = 3.00 102 cm. as shown in Figure P24.7, simultaneously broadcast identical signals at the same the signals. (a) If the car is at the position of the second maximum wavelength. A car travels due north along a straight line at position x = 1.00 103 m from the center point between the antennas and its radio receives the signal. (a) If the car is at the position of the second maximum after that at point O when it has traveled a distance of y = 4.00 102 m northward, what is the wavelength of the signals? (b) How much farther must the car travel from thus position to encounter the next minimum in reception? Hint: Do not use the small-angle approximation in this problem.
Two radio antennas separated by d = 3.00 102 cm. as shown in Figure P24.7, simultaneously broadcast identical signals at the same the signals. (a) If the car is at the position of the second maximum wavelength. A car travels due north along a straight line at position x = 1.00 103 m from the center point between the antennas and its radio receives the signal. (a) If the car is at the position of the second maximum after that at point O when it has traveled a distance of y = 4.00 102 m northward, what is the wavelength of the signals? (b) How much farther must the car travel from thus position to encounter the next minimum in reception? Hint: Do not use the small-angle approximation in this problem.
The 305-m-diameter Arecibo radio telescope pictured in Figure 4.20 detects radio waves with a 4.00-cm average wavelength. (a) What is the angle between two just-resolvable point sources for this telescope? (b) How close together could these point sources be at the 2 million light-year distance of the Andromeda Galaxy? Figure 4.20 A 305-m-diameter paraboloid at Arecibo in Puerto Rico is lined with reflective material, making it into a radio telescope. It is the largest curved focusing dish in the world. Although D for Arecibo is much larger than for the Hubble Telescope, it detects radiation of a much longer wavelength and its diffraction limit is significantly poorer than Hubble’s. The Arecibo telescope is still very useful, because important information is carried by radio waves that is not carried by visible light. (credit: Jeff Hitchcock)
(a) The ideal size (most efficient) for a broadcast antenna with one end on the ground is onefourth the wavelength (/4) of the electromagnetic radiation being sent out. If a new radio station has such an antenna that is 50.0 m high, what frequency does it broadcast most efficiently? Is this in the AM or FM band? (b) Discuss the analogy of the fundamental resonant mode of an air column closed at one end to the resonance of currents on an antenna that is one-fourth their wavelength.
1. It takes 3.8 x 10 -5 s for a pulse of radio waves from radar to reach a plane bounce back to the radar. How far is the plane from the radar? Your answer must be a whole number, have no spaces and commas, and have a unit. Sample Answer: 4500m 2. The X-ray used by your dentist has a wavelength of 15 nm. What is its energy? Your answer must have 2 decimal places, have no spaces, and have a unit. Sample Answer: 1.23x10e-35J 3. The X-ray used by your dentist has a wavelength of 15 nm. What is the frequency? Your answer must not contain spaces. Sample Answer : 1x10e12s
Light from a chromatic light source strikes a surface. Ten percent of the light isabsorbed and 40% is reflected.a. What percentage of the light incident on the surface is transmitted?b. What are the reflectance, absorptance, and transmittance values?c. Is the surface translucent or opaque?
Consider two coherent sources producing EM waves at f=2.7×1014[Hz] in vacuum. The path difference between the two waves is 3.0[nm]. What is the phase difference between the two waves? A.0.017[rad] B.0.019[rad] C.0.17[rad] D.0.19[rad]
1. Imagine that you have two identical perfect linear polarizers and a source of natural light. Place them one behind the other and position their transmission axes at 0° and 50°, respectively. Now insert between them a third linear polarizer with the transmission axes 25°. If 1000 W/m? ofunpolarized light is incident, how much will emerge with and without the middle polarizer in place?