Question

2. Our sun has a power output of roughly 3.87 1026 watts (W). This energy is transmitted essentially uniformly in all directions. By the time this radiation reaches the Earth, which has an average distance from the sun of 1.50 x 10" m, what is the intensity? (Recall that intensity is defined to be power per unit area). 3. The energy from the sun is primarily in the infrared and visual wavelengths. The following table gives the distribution of the sun's energy over the given regions of the electromagnetic spectrum. Spectral Region Wavelength Infrared Visible UV-A UV-B UV-C > 700 nm 400-700 nm 320 400 nm 280-320 nm < 280 nm % of Sun's Energy 49.4 42.3 6.3 1.5 0.5 With this in mind, what is the intensity contained just within the UV-B range? 4. Thankfully, the Earth's atmosphere blocks a fair amount of this radiation as well. Only about 25% of the incoming UV-B radiation makes it to the surface of the earth. What is the intensity of the UV-B radiation at the surface of the earth? 5. On a clear summer day with the sun overhead, how much energy is absorbed by the skin on your exposed forearms (assume a total surface area of 0.1 m) if you're out in the sun, unprotected, for three hours and all of the incident UV-B radiation is absorbed? (Most sunscreens are designed to absorb this radiation so that less penetrates into your skin and damage.) causes

Electromagnetic Wave Questions

Answer 1

Sol@ Power outbut (P) = 3.87% 1026 waltim) distance from sund (ar) 1.50 x 10m As we know the Relation (1) Inteurity (Average I= 2 Р u0912 As = 3187 X 1026 (1150 XIO'Bun I=1.3698103 W/m² Hence, the In Intensity 1.378 103 W/m2