a) 0.321 ly
b) 0.321 light years is not far in astronomical terms. Alien life would need to transmit at tremendous power in order for their radio transmissions to be detectable. Their radio signal also needs to be stronger than background noise in order to be distinguishable. Therefore it is unlikely that radio transmissions from alien life will ever be detected.
The Pauli exclusion principle state that : D. Two electrons occupy the same orbital only if they have opposite spins
This happen because he stated that in an atom or molecule, two electrons CANNOT have same four electronic quantum numbers
hope this helps
