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A changing electric field will generate a magnetic field. Which of the following best describes the direction of the magnetic field that accompanies the transmission of an FM signal as described in the passage?
A. Parallel to the ground and perpendicular to the direction of propagation.
B. Perpendicular to the ground and perpendicular to the direction of propagation
C & D-wrong.
Explanation: The electric field vector, the magnetic field vector, and the vector that points in the direction of propagation are always mutually perpendicular. If the FM signal is plane-polarized with the electric field E parallel to the ground (as stated in the last paragraph of the passage), then the answer must be A.
Last paragraph of the passage: The AM broadcast band includes frequencies from….while the FM bands includes frequencies from….it's also known that AM signals tend to have greater range than Fm signals. The audible spectrum contains frequencies between 20 Hz and 20,000 Hz, although waves with frequencies greater than 10,000 Hz are not transmitted effectively by radio signals. FM signals traveling across the surface of the Earth are plane polarized perpendicular to the ground.
Where does it say in this paragraph that the "FM signal is plane-polarized with the electric field E parallel to the ground?" What's the relationship between the bolded sentences?
A. Parallel to the ground and perpendicular to the direction of propagation.
B. Perpendicular to the ground and perpendicular to the direction of propagation
C & D-wrong.
Explanation: The electric field vector, the magnetic field vector, and the vector that points in the direction of propagation are always mutually perpendicular. If the FM signal is plane-polarized with the electric field E parallel to the ground (as stated in the last paragraph of the passage), then the answer must be A.
Last paragraph of the passage: The AM broadcast band includes frequencies from….while the FM bands includes frequencies from….it's also known that AM signals tend to have greater range than Fm signals. The audible spectrum contains frequencies between 20 Hz and 20,000 Hz, although waves with frequencies greater than 10,000 Hz are not transmitted effectively by radio signals. FM signals traveling across the surface of the Earth are plane polarized perpendicular to the ground.
Where does it say in this paragraph that the "FM signal is plane-polarized with the electric field E parallel to the ground?" What's the relationship between the bolded sentences?