Please help me solve these 2 problems. I have no idea where to even start. Point
ID: 1376272 • Letter: P
Question
Please help me solve these 2 problems. I have no idea where to even start. Points will be awarded!!
9. A 40.0-W laser emits a beam of light 9.0 mm in diameter. The laser is aimed at the Moon. By the time it reaches the Moon, the beam has spread out to a diameter of 85 km. What was the intensity of the light just as it first exited the laser? (Intensity has units of power per unit area)
10. What is the value of the intensity where it hits the moon? (Assume there is no absorption in the atmosphere on the way)
9. A 40.0-W laser emits a beam of light 9.0 mm in diameter. The laser is aimed at the Moon. By the time it reaches the Moon, the beam has spread out to a diameter of 85 km. What was the intensity of the light just as it first exited the laser? (Intensity has units of power per unit area) 10. What is the value of the intensity where it hits the moon? (Assume there is no absorption in the atmosphere on the way)Explanation / Answer
9.
the emitted intensity is = power / area
the emitted inntensity is = 40 / ( pie * (0.009)^2) / 4
the emitetd intensity = 40 / 6.3585* 10^-5 = 629079.185
the emitted intensity is 0.629 * 10^6 W / m^2
10.
the intensity on the moon is= power / area beam spread out on moon
the intensity on the moon is = 40 / (3.14 * 85 *85 * 10^6)/4
the intensity on the moon is = 40 / 5671.625 * 10^6
the intensity on the moon is = 7.052 * 10^-9 W/m^2