E=12V(Given)LetEobethepeakvoltageofthebulb.LetRandTbetheresistanceandtemperatureoftheelectricbulb.Since,heatproducedinaresistorbypassingAlternatingcurrentissameasheatproducedbydirectcurrentinaresistorinsametime.So,i2RT=i2rmsRT=>E2R2RT=E2rmsR2RT=>E2=E2o2(Asweknow,Erms=Eo√2)=>E2o=2E2=2×122=>Eo=√2×122=12√2=16.97V=17V