Question

An electric device uses 650 watts of power. If the voltage is 120 volts, what is the resistance?

Answer 1

22.25 ohm

Answer 2

Use the equation P =(E^2)/R. Substitute the given values
650 = (120)(120)/R
R = (120X120)/650
R = (24X12)/13
R = 288/13 Ohms
R = 22.1538 Ohms

Answer 3

Hello, simply first we calculate Current in Amperes.
I (current)= P (power in watts) / Voltage(in volts )
I= 650/120 , in Ampere
I=5.416 A (Ampere)
now Applying Ohm's Law V=IR we have V=120V and I=5.416A and R=?
R=V/I , So, R=120/5.416=22.156573
so R=22.156573 ohms [where ohms represent by symbol Ω]..

So Finally R=22.156573Ω

Thanks.

Answer 4

Note that their are 3 results posted. The difference is in the manner in which "rounding off" was accomplished. The value of 22.1538 Ohms was obtained by keeping the answer in fractional form until the final calculation.