When neutral disconnected, lamps are in series connection,
So, for series connection current is same for both Lamp,
So, Resistance of 100 W Lamp is more compared to 150 W Lamp.
Hence after neutral connection disconnect 100 W Lamp is more brighter than the 150 W Lamp.
Slip, s = (Ns - Nr)/Ns
Ns = 120f/P
Ns = 1500 rpm
s = (1500 - 1425)/1500
s = 0.05
%s = 5%
A wire pilot is generally economical for distances up to 5 or 10 miles, beyond which a carrier-current pilot usually becomes more economical.