The human heart creates the body's largest electromagnetic eld. During normal beating, an electrocardiogram measures a voltage of 2.7 mV between two electrical contact pads on the chest that are separated by 25 cm. This creates an electromagnetic wave with a frequency of 1.2 Hz. (a) What is the wavelength of this wave? (b) What is the maximum value of the electric eld in this wave? (c) What is the maximum value of the magnetic eld? (cl) What is the average total energy density in the wave? (a) Number 2.5e8 Units (b) Number Lie-2 Units V/m v (cl) Number _ Units J/m"3 WI solution V = 2.7mv f = 12HE separation (d) = 85cm a) wave length 1 = 9 C - lightspeed = 3x 108 25 x 108 m 1- 2 b) Maximum value of electric field. E = Y = 2 7X10- 3 v 0.25 = 10.8 x 10- V/m = 1.08 x 10 - 2 V / m E 1 . 1 X 10 2 V /m ( ) Max. magnetic field B = E = 1.1X10-2 3. 67 x 10 - 11 T 3x 108 d) Avg. total energy density. E- peremititrity for U = ( EO E + B ? 6 ) 12 free space - =[ B. 85 X 10- 12 x ( 1. 1 X 102 ) + ( 3. 67 X10-11 ) Mo = permiabillity 4 TT x 10-7 1. 09 1 X 10-15 J/m 3