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2. [0.33/1 Points] DETAILS PREVIOUS ANSWERS WAUNIPHYSAV1 32.P.004.TUTORIAL. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER An oscillating dipole antenna 1.98 m long with a maximum 35.5 mV potential creates a 500 Hz electromagnetic wave. (a) What is the maximum electric field strength created? 0.01792 V/m (b) What is the corresponding maximum magnetic field strength in the electromagnetic wave? 7.03e-11 X What is the relationship between the electric field and the magnetic field in an electromagnetic wave? T (c) What is the wavelength of the electromagnetic wave? m 29 Tutorial4. [0/1 Points] DETAILS PREVIOUS ANSWERS WAUNIPHYSAV1 32.P.010. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER The magnetic field in a plane electromagnetic wave is represented by the equation B = Bmax sin(ky - wt)i where Bmax = 5.98 x 10- T and k = 4.29 x 107 /m. (Assume a standard xyz right-handed coordinate system.) (a) What is the magnitude and direction of the electric field at the instant the magnetic field is a maximum? (Express your answer in vector form.) Emax = 180k For a plane electromagnetic wave, how are the amplitudes of the electric and magnetic fields related? What is the direction of propagation of the wave in this case? Review the right-hand rule for vector product of the electric and magnetic field vectors. V/m (b) What is the wavelength of the wave? nm (c) What is the frequency of the wave? Hz5. [-11 Points] WAUNIPHYSAV1 32.P.014. ASK YOURTEACHER PRACI'ICE ANOTHER Prior to the switch to digital television broadcasting, and to the popularity of cable television, many homes had outdoor TV antennas. Tv-reception antennas for VHF (channels 2 through 13) were constructed with cross wires supported at their centers, as shown in the gure below. The ideal length for the cross wires is one-half the wavelength to be received, with the more expensive antennas having one for each channel. Suppose you measure the lengths of the wires for channels 6 and 8 and nd them to be 0.961 m and 0.711 m long, respectively. 9 10 11 12 13 What Is the frequency for channel 67 HZ What is the frequency for channel 3? EH2 6. [-/1 Points] DETAILS WAUNIPHYSAV1 32.P.019. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER (a) What is the wavelength of 122-MHz radio waves used in an MRI unit? (Give your answer to at least two decimal places.) (b) If the frequencies are swept over a +1.20% range centered on 122 MHz, what is the range of wavelengths broadcast? (Give your answers to at least two decimal places.) minimum m maximum 7. [-/1 Points] DETAILS WAUNIPHYSAV1 32.P.023. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER A pulsar is a type of rotating neutron star that emits a beam of electromagnetic radiation. Imagine a pulsar that is moving toward Earth at a speed of 720.00 km/s. It emits mostly radio waves with a wavelength (at the source) of 131.00 cm. What is the observed wavelength of this radiation on Earth? (Assume the Earth is stationary. Consider the speed of light c = 3.0000 x 108 m/s. Give your answer to at least five significant figures.) cm 8. [0/1 Points] DETAILS PREVIOUS ANSWERS WAUNIPHYSAV1 32.P.024. TUTORIAL. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER The helium-neon lasers most commonly used in student physics laboratories have average power outputs of 0.250 mW. (a) If such a laser beam is projected onto a circular spot 3.94 mm in diameter, what is its intensity? W/m2 (b) Find the peak electric field strength. 5.4 X What is the relationship between intensity and electric field strength? V/m c) Find the peak magnetic field strength. 1.8e-08 X What is the relationship between electric field strength and magnetic field strength in an electromagnetic wave? T 129 Tutorial