Answers

2015-04-01T19:34:20+05:30
R = 0.512x10^(-10)(n^2/z) metre
n is orbit no. 
z is atomic number.
here, n=2, z=2
v=2.18X10^6(z/n) ms^(-1)
E=31.6 (Z^2/ n^2) ev(electron volt)
potential energy= 2E
kinetic energy= -E
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