Spesifikasi solder listrik 220 volt/60 watt. solder tersebut dipasang pada tegangan 110 volt. daya ada solder listrik tersebut adalah ...

A. 15 watt

B. 20 watt

C. 35 watt

D. 40 watt

One of the useful forns of the formula for electrical power is: Power = (voltage squared) / (resistance). Knowing that power is proportional to (voltage squared), we can see that if the voltage is reduced to 1/2, the power is reduced to 1/4 of its original value. The 220volt/60watt appliance, when operated on 110 volts, dissipates 60/4 = 15 watts.