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Estimate the approximate maximum deflection of the electron beam near the center of a CRT television screen due to the Earth s 5.0 × 10–5 T field. Assume the screen is 18 cm from the electron gun, where the electrons are accelerated (a) by 2.0 k V, or (b) by 28 kV. Note that in color TV sets, the beam must be directed accurately to within less than 1 mm in order to strike the correct phosphor. Because the Earth’s field is significant here, mu-metal shields are used to reduce the Earth’s field in the CRT. (See Section 23–9.)
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