First, let's calculate it's value: P(r) = (E² * r) / (r + r )² = E² / (4r) Now to check whether this is a maximum, we can compare it with other values of the function, in points between R = r and the other zeroes of P'(R), which here is R = -r. If P reaches a maximum in R=r, that would mean that (1) we can evaluate P in any point R>r and its value should be less than P(r), you can do this for, e.g. R=2r, which yields P(2r) = (2E²)/(9r), which is obviously smaller than P(r).
Also it means that (2) we can evaluate P in any point R so that -r < R < r, and this value should be smaller than P(r). For example, if we take R to be 0, P(R)=0, which is also smaller than P(r). Thus we have proven that P reaches a maximum in r, with corresponding value E² /(4r).
Radiation is the only one that can pass through a vaccum (like space). You need a medium for conduction and convection to work. Therefore the answer is radiation.
D When it is stretched ready to shoot at the wall
Answer: An emission line occurs when an electron drops down to a lower orbit around the nucleus of an atom and looses energy.
An absorption line also occurs when any electron move to a higher orbit by absorbing energy.
Each atom has a unique way of using some space of the orbits and can absorb only certain energies or wavelengths.
Explanation:
Answer:
E= 2.158× 10*5N/C
Explanation:
K= 8.99×10*9, q= 6×10*-6C, d= 0.5m
E= kq/d*2
E= (8.99×10*9× 6×10*-6)/0.5*2
E= 215760
E= 2.158 ×10*5N/C