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.
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.
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.
Problem 4: Consider the 100-MHz radio waves used in an MRI device.
Part (a) What is the wavelength, in meters, of these radio waves?
λ = 3
Part (b) If the frequencies are swept over a ±12.5 MHz range centered on 100 MHz, what is the minimum, in meters, of the range of wavelengths emitted?
λmin =
Part (c) What is the maximum, in meters, of this wavelength range?
λmax =
Scientists use laser range finding to measure the distance to the moonwith great accuracy. A very brief (100 ps) laser pulse, with a wavelengthof 532 nm, is fired at the moon, where it reflects off an array of 100 4.0-cm-diameter mirrors placed there by Apollo 14 astronauts in 1971. The reflected laser light returns to earth, where it is collected by a telescope and detected. The average earth-moon distance is 384,000 km. The laser beam spreads out on its way to the moon because of diffraction, reaching the mirrors with an intensity of 300 W/m2. The reflected beam spreads out even more on its way back because of diffraction due to the circular aperture of the mirrors.a. What is the round-trip time for the laser pulse to travel to the moon and back?b. If we want to measure the distance to the moon to an accuracy of 1.0 cm, how accurately must the arrival time of the returning pulse be measured?c. Because of the spread of the beam due to diffraction, the light arriving at earth from one…
Problem 4: Consider the 100-MHz radio waves used in an MRI device.
Part (a) What is the wavelength, in meters, of these radio waves? Part (b) If the frequencies are swept over a ±14 MHz range centered on 100 MHz, what is the minimum, in meters, of the range of wavelengths emitted?
Part (c) What is the maximum, in meters, of this wavelength range?
Physics for Scientists and Engineers: A Strategic Approach, Vol. 1 (Chs 1-21) (4th Edition)
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