Question

Question 15 (1 point) An electromagnetic standing wave in air of frequency 750 MHz is set up between two conducting planes 80.0 cm apart. At which positions between the planes could a point charge be placed at rest so that it would remain at rest? 1 place, halfway between the planes. 2 places, 20 cm from each plane, between the planes. 4 places, 10 cm from each plane, and 20 cm from each plane, between the planes. There is no such spot between the planes where this is possible.

Answer 1

Given that, X = C/f = 40 cm, X = 20, 40, 60 cm frequency f = 750 m Hz = 750 times 10^6 Hz EM Waves are developed between the two plates then the distance at the nodes = delta x = lambda/2 therefore The distance between the two node = lambda/2 so delta x = lambda/2 = c/2f = 3 times 10^8 m/s/2(750 times 10^6 Hz) = 20 * The halfway distance between the places is 80 cm * So in between these two places the nodal points are forms at a distances of 20 cm, 40 cm, 60 cm and 80 cm respectively * So the these point charge is at rest.