1. At a certain location, electromagnetic wave 1 is measured to have a maximum e

Question

1. At a certain location, electromagnetic wave 1 is measured to have a maximum electric field of Eo = 52 N/C, and electromagnetic wave 2 is measured to have a maximum magnetic field of Bo= 1.5 a. (5 points) Calculate the intensity of each wave b. (5 points) If the electromagnetic waves are being measured 0.94 km from their light sources (assume that they are emitting light uniformly in all directions), how much power is each source emitting? By how many 40 W incandescent light bulbs would each light source need to be replaced to emit the same amount of power? c. (5 points) Suppose an average human sun bathes in the light from wave 2 for 45 minutes If we assume that this person exposes 1.0 m2 of their skin to this light and that none of the light is reflected by the skin, how much energy is absorbed into their skin? If you could somehow utilize this energy to lift a 150. kg person on the surface of the Earth, how high could the person be lifted? d. (5 points) Assume that both light waves are initially unpolarized. We decide to send the higher intensity light wave through a polarizer-analyzer - combination so that its final intensity matches that of the lower (unpolarized) intensity light wave. If the transmission axis of the first polarizer is horizontal, how must the transmission axis of the analyzer be oriented so that the light intensities match? -- Polarizer Analyzer

Explanation / Answer

1. (A) I = c Bo^2 / (2 u0) = Eo^2 / 2 u0 c

I1 = (52^2) /(2 x 4pi x 10^-7 x 3 x 10^8)

I1 = 3.59 W/m^2

I2 = (3 x 10^8) (1.5 x 10^-6)^2 / (2 x 4pix 10^-7)

I2 = 537.2 W/m^2

(B) from 40 W bulb,

I = P / (4pi r^2) = 40 / 4pi(0.94 x 10^3)^2

I = 3.602 x 10^-6 W/m^2

for wave 1: n = I1 / I =9.97 x 10^5

for wave 2: n = I2 / I = 1.49 x 10^8

(C) Energy absorbed = (537.2) (1 m^2) (45 x 60 s)

= 1.45 x 10^6 J

h = (1.45 x 10^6) / (150 x 9.8)

h = 987 m

(d) 3.59 = (537.3/2) (cos(90 -theta))^2  

90 -theta = 6.6 deg

Related Questions

Navigate

• Browse (All)
• Browse 1
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.