Introduction To Health Physics
Introduction To Health Physics
5th Edition
ISBN: 9780071835275
Author: Johnson, Thomas E. (thomas Edward), Cember, Herman.
Publisher: Mcgraw-hill Education,
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Chapter 14, Problem 14.25P
To determine

The power density, where the meter reading is +2.5 dB.

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Radio waves and microwaves are used in therapy to provide “deep heating” of tissue because the waves penetrate beneath the surface of the body and deposit energy. We define the penetration depth as the depth at which the wave intensity has decreased to 37% of its value at the surface. The penetration depth is 15 cm for 27 MHz radio waves. For radio frequencies such as this, the penetration depth is proportional to √λ, the square root of the wavelength. If the frequency of the radio waves is increased, the depth of penetrationA. Increases.      B. Does not change.        C. Decreases.
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