High microwave intensities can cause biological damage through heating of tissue; a particular concern is cataract formation. The U.S. Food and Drug Administration limits microwave
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- A community plans to build a facility to convert solar radiation to electrical power. The community requires 2.60 MW of power, and the system to be installed has an efficiency of 30.0% (that is, 30.0% of the solar energy incident on the surface is converted to useful energy that can power the community). Assuming sunlight has a constant intensity of 1 200 W/m2, what must be the effective area of a perfectly absorbing surface used in such an installation?arrow_forwardIn Microwave diathermy The frequency used is .a 750MHZ .b 900MHZ .C 800MHZ .d 600MHZarrow_forwardAt what distance from a 10 mW point source of electromagnetic waves is the electric field amplitude 0.010 V/m?arrow_forward
- Consider a bright star in our night sky. Assume its distance from Earth is 86.3 light-years (ly) and its power output is 4.00 x 1028 W, about 100 times that of the Sun. One light-year is the distance traveled by light through a vacuum in one year. (a) Find the intensity of the starlight at the Earth. W/m² (b) Find the power of the starlight the Earth intercepts. (The radius of Earth is 6.38 x 106 m.) MW Need Help? Read Itarrow_forwardConsider a bright star in our night sky. Assume its distance from Earth is 84.9 light-years (ly) and its power output is 4.00 × 1028 W, about 100 times that of the Sun. One light-year is the distance traveled by light through a vacuum in one year. (a) Find the intensity of the starlight at the Earth. W/m² (b) Find the power of the starlight the Earth intercepts. (The radius of Earth is 6.38 x 106 m.) MWarrow_forwardA space probe 2.0 x 1010 m from a star measures the total intensity of electromagnetic radiation from the star to be 5.0 x 103 W/m2 . If the star radiates uniformly in all directions, what is its total average power output?arrow_forward
- The intensity of electromagnetic energy from the Sun reaching the Earth is 1,390 W/m?. Earth is about 1.5 x 1011 m from the Sun and Saturn is about 10 times further, how much power would a 1.00 m2 solar panel receive at the distance of Saturn? Provide the solution:arrow_forwardWhat is the radiation pressure 1.2 m away from a 600 W lightbulb? Assume that the surface on which the pressure is exerted faces the bulb and is perfectly absorbing and that the bulb radiates uniformly in all directions. Number Units Use correct number of significant digits; the tolerance is +/-1 in the 2nd significant digitarrow_forwardThe damage threshold for the retina is 100 W/m². This means that a damage to the retina can occur at an average intensity greater than this. The light coming from a 5.0 mW green laser has a diameter of 1.2 mm. (a) Will this laser exceed the damage threshold for the retina? (b) What are the maximum values of the electric and magnetic fields of the beam coming from this laser? 2.arrow_forward
- A space probe 2.0 * 1010 m from a star measures the total intensity of electromagnetic radiation from the star to be 5.0 * 103 W/m2. If the star radiates uniformly in all directions, what is its total average power output?arrow_forwardA microwave source produces pulses of 21.0 GHz radiation, with each pulse lasting 1.00 ns. A parabolic reflector with a face area of radius R = 8.50 cm is used to focus the microwaves into a parallel beam of radiation, as shown in the figure below. The average power during each pulse is 25.0 kW. (a) What is the wavelength of these microwaves? cm (b) What is the total energy contained in each pulse? μJ (c) Compute the average energy density inside each pulse. mJ/m³ 3 (d) Determine the amplitude of the electric field and magnetic field in these microwaves. Emax kv/m μT B. max (e) Compute the force exerted on the surface during the 1.00 ns duration of each pulse. Assume this pulsed beam strikes an absorbing surface. UNarrow_forwardi %A. Ilı. ۱۲:۲۸ د رابع ب.docx 1. In a communication system, a power of 10 dBm is transmitted through a dipole antenna. The power received at a distance of 1 m is less than the transmitted power by 31.4 dB. If the propagation environment has a power exponent value of 2.7, determine: a) The system frequency. b) The power received by a receiving antenna of 5dB gain, located at 2.0 km from the transmitting antenna. c) The propagation channel path loss. IIarrow_forward