Prior to the switch to digital television broadcasting, and to the popularity of
ID: 1374097 • Letter: P
Question
Prior to the switch to digital television broadcasting, and to the popularity of cable television, many homes had outdoor TV antennas. TV-reception antennas for VHF (channels 2 through 13) were constructed with cross wires supported at their centers, as shown in the figure below. The ideal length for the cross wires is one-half the wavelength to be received, with the more expensive antennas having one for each channel. Suppose you measure the lengths of the wires for channels 7 and 5 and find them to be 0.830 m and 1.080 m long, respectively.
What is the frequency for channel 7?
What is the frequency for channel 5?
http://www.webassign.net/webassignalgphys1/24-p-016.gif
Explanation / Answer
Channel 7
wavelength = length *2 = 0.83*2 = 1.66 m
Frequency = speed / wavelength = 3 x 10^8 / 1.66 = 1.08 x 10 8 Hz
Channel 5
wavelength =2* length = 2*1.08 = 2.16
Frequency = speed / wavelength = 3 x 10^8 / 2.16 = 1.38 x 10 8 Hz
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.