Answer:
Plane spacing, 
Explanation:
It is given that,
Wavelength of x-ray, 
Angle the x-ray made with a set of planes in a crystal causing first order constructive interference is 30 degrees
We need to find the plane spacing. It is based on Bragg's law such that,

d is plane spacing
n = 1 here

So, the plane spacing is
.
Average acceleration: velocity/time
5/4= 1.25 m/s² Acceleration
Hope I helped :)
Its most likely C. Remember the bigger the vehicle the bigger the area it needs to make a safe turn.
This true it will be visible if they are covered
Answer:
periodic means appearing or occurring at intervals.
Explanation: