A particle of mass m moves in circular orbits with potential energy V(r)=Fr, where F is a positive constant and r is its distance from the origin. Its energies are calculated using the Bohr model. If the radius of the particle's orbit is denoted by R and its speed and energy are denoted by v and E, respectively, then for the nth orbit (here h is the Planck's constant)
a. R∝n1/3 and v∝n2/3
b. R∝n2/3 and v∝n1/3
c. E=23(4π2mn2ℏ2F2)1/3
d. E=2(4π2mn2ℏ2F2)1/3