Part A Scientists use laser range-finding to measure the distance to the moon with great accuracy. A brief laser pulse is fired at the moon, then the time interval is measured until the "echo" is seen by a telescope. A laser beam spreads out as it travels because it diffracts If A = 511 nm , what is the minimum diameter of the circular opening from which the laser beam emerges? The earth-moon distance is 384,000 km through a circular exit as it leaves the laser. In order for the reflected Express your answer to two significant figures and include the appropriate units. light to be bright enough to detect, the laser spot on the moon must be no more than 1.0 km in diameter. Staying within this diameter is accomplished by using a special large-diameter laser. ? D= Value Units Submit Request AnswerA Michelson interferometer operating at a 400 nm wavelength has a 3.96mlong glass cell in one arm. To begin, the air is pumped out of the cell and minor M is adjusted to produce a bright spot at the center of the interference pattern. Then a valve is opened and air is slowly admitted into the cell. The index of refraction of air at 1.00 atm pressure is 1.00028. Part A How many.r brightdarkbright fringe shifts are observed as the cell lls with air? R_eouest