Comment on the relationship between the inter-element distance (7.5cm) and a wavelength of an EM wave (0.15m). What would be the effect on the inter-element distance if an EM wave at a higher frequency was used, assuming all other parameters were required to stay the same.

A small helium-neon laser has a power output of 2.5 mW What is the electromagnetic energy in a 1.0-m length of the beam?

Suppose you are located 180 in from a radio transmitter. (a) How many wavelengths are you from the transmitter if the station calls itself 1150 AM? (The AM band frequencies are in kilohertz.) (b) What if this station is 98.1 FM? (The FM band frequencies are in megahertz.)

Lunar astronauts placed a reflector on the Moon's Surface, off which a laser beam is periodically reflected. The distance to the Moon is calculated from the round-trip time. (a) To what accuracy in meters can the distance to the Moon be determined, if this time can be measured to 0.100 ns? (b) What percent accuracy is this, given the average distance to the Moon is 3.84108m ?

The voltage across a parallel-plate capacitor with area A=800cm2 and separation d = 2 mm varies sinusoidally as V = (15 mV) cos (150t), where t is in seconds. Find the displacement current between the plates.

Certain orientations of a broadcast television antenna give better reception than others for a particular station. Explain.

At what distance does a 100-W lightbulb produce the same intensity of light as a 75-W lightbulb produces 10 m away? (Assume both have the same efficiency for converting electrical energy in the circuit into emitted electromagnetic energy.)

Radio station WWVB, operated by the National Institute of Standards and Technology (NIST) from Fort Collins, Colorado, at a low frequency of 60 kHz, broadcasts a time synchronization signal whose range covers the entire continental US. The timing of the synchronization signal is controlled by a set of atomic clocks to an accuracy of 101012 s, and repeats every 1 minute. The signal is used for devices, such as radio-controlled watches, that automatically synchronize with it at preset local times. WWVB's long wavelength signal tends to propagate close to the ground. (a) Calculate the wavelength of the radio waves from WWVB. (b) Estimate the error that the travel time of the signal causes in synchronizing a radio controlled watch in Norfolk, Virginia, which is 1570 mi (2527 km) from Fort Collins, Colorado.

Design a window for a 4GHZ EM wave travelling between vacuum and BeO.

If electric and magnetic field strengths vary sinusoidally in time, being zero at t =0, then E =E0 sin 2πft and B= B0 sin 2πft. Let f =1.00 GHz here. (a) When are the field strengths first zero? (b) When do they reach their most negative value? (c) How much time is needed for them to complete one cycle?