10) A network of similar induction coils are connected together in a circuit carrying AC of frequency 50Hz. If when they are connected in series their induc ve reactance was 50 Ohm
and when they connected in parallel was 2 Ohm , Ignoring the Onmic resistance and the
mutual induction between them Calculate:
a) Number of coils
b) The inductive reactance for each coil
c) The self-induc on coe
cient of each coil
(5 Coils , 10 Ohni, 31.8 x 10--8 H)

Uranium has two naturally occurring isotopes. 238u has a natural abundance of 99.3% and 235u has an abundance of 0.7%. it is the rarer 235u that is needed for nuclear reactors. the isotopes are separated by forming uranium hexafluoride uf6, which is a gas, then allowing it to diffuse through a series of porous membranes. 235uf6 has a slightly larger rms speed than 238uf6 and diffuses slightly faster. many repetitions of this procedure gradually separate the two isotopes. what is the ratio of the rms speed of 235uf6 to that of 238uf6? express your answer to five significant figures.