2. [-/1 Points] DETAILS 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? V /m (b) What is the corresponding maximum magnetic field strength in the electromagnetic wave? (c) What is the wavelength of the electromagnetic wave? m 129 Tutorial 3. [-/1 Points] DETAILS WAUNIPHYSAV1 32.P.009. MY NOTES ASK YOUR TEACHER PRACTICE ANOTHER During normal beating, the heart creates a maximum 3.85-mV potential across 0.260 m of a person's chest, creating a 1.00-Hz electromagnetic wave. (a) What is the maximum electric field strength created? V/m (b) What is the corresponding maximum magnetic field strength in the electromagnetic wave? IT (c) What is the wavelength of the electromagnetic wave? m4. [-/1 Points] DETAILS 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 10-7 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 = V/m (b) What is the wavelength of the wave? nm (c) What is the frequency of the wave? Hz5. [-I1 Points] WAUNIPHYSAV1 32.P.014. ASK YOUR TEACHER PRACTICE 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 6? HZ What is the frequency for channel 8? Hz 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 m 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. [-/1 Points] DETAILS 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. V/m (c) Find the peak magnetic field strength. T 123 Tutorial