Atopaz crystal has an interplanar spacing (d) of 1.36 å (1 å =1×10^[−10] m). calculate the wavelength of the x-ray that should be used if θ = 15° (assume n = 1).

Alidded glass container is filled with a colored gas. after a period of time, it is observed that the gas is uniformly spread throughout the box and that the movement has slowed considerably. next, a warm iron plate is carefully placed under the box. why is there resumed movement of the gas in the container?