In the rotation speed measurement by a stroboscope why to us

In the rotation speed measurement by a stroboscope, why to use the \"double\" or \"hair function in frequency adjustment of stroboscope? In the rotation speed measurement by a tachometer, what is the main purpose to compare the pdf of rotating speed against Gaussian distribution? What is the difference between the standard equation of a given type of thermocouple (with a reference point at 0 degree C) and the equation of the same thermocouple with a floating reference point at the ambient temperature (say, 25 degree C)? You may use a schematic graph or example to explain. Why does a thermocouple do not need calibration (and hence used as a standard temperature to calibrate other temperature methods)? Why is a commercial thermocouple typically more reliable than a home-made one (assuming the same thermocouple materials are used)? A truck-load (L) is determined by the weight difference between an unloaded truck (W_1) and the one with load (W_2). (a) If the weights are measured by the same load cell with the same absolute error margin (plusorminus uw), what is the uncertainty of L? (b) If the error margin of load-cell measurement is determined by a fixed percentage (say, plusminus 1%) of the nominal weight, what is the uncertainty of L? The coefficients of a thermistor, alpha and beta, can be determined either by a two-point calibration (e.g., R_1 at T_1 = 0 degree C and R_2 at T_2 = 100 degree C) or by a curve fitting using a series of measurements {R_i, T_i} (i = 1, N}. Which one is more accurate? Why?

Solution

1) Double or half function is used for large adjustment rate change. Basically stroboscope is a tool which uses bright flashing light to allow the users to view the object which are rapidly moving in periodic order.when the frequency of the matching light matches with the moving speed of the object the object can be appeared to be stationary.

So double or half function is used for adjustment to match frequency of moving object with flashing light.