A certain type of radio antenna is called a quarter-wavelength antenna, because its length is equal to one-quarter of the wavelength to be received. If you were going to make such antennae for the AM and FM radio bands by using the middle frequencies of each band, what lengths of wire would you use?
Answer to relevant QuestionsMicrowave ovens can have cold spots and hot spots due to standing electromagnetic waves, analogous to standing wave nodes and antinodes in strings (Fig. 20.32). (a) The longer the distance between the cold spots, (1) the ...A flat coil of copper wire consists of 100 loops and has a total resistance of . The coil diameter is 4.00 cm and it is in a uniform magnetic field pointing toward you (out the page). The coil orientation is in the plane of ...(a) A square loop of wire with sides of length 40 cm is in a uniform magnetic field perpendicular to its area. If the field’s strength is initially 100 mT and it decays to zero in 0.010 s, what is the magnitude of the ...A 25-Ω resistor is wired directly across a 120-V ac source. What happens to the time-average power, rms voltage, and rms current when the resistor’s value changes to 50 Ω? The current in a resistor is given by I = (8.0 A) sin (40πt) when a voltage given by V = (60 V) sin (40πt) is applied to it. (a) What is the resistance value? (b) What are the frequency and period of the voltage source? ...
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