L Lizzy A New member Jun 12, 2009 #1 20 A 4.50-volt personal stereo uses 1950 joules of electrical energy in one hour. What is the electrical resistance of the personal stereo?
20 A 4.50-volt personal stereo uses 1950 joules of electrical energy in one hour. What is the electrical resistance of the personal stereo?
H hobart_elf New member Jun 12, 2009 #2 1950/3600 = 0.542 watts. From P = v^2/R then R = V^2/P which is 37.38 ohms.
N nozar nazari New member Jun 12, 2009 #3 P=1950/3600 joules/sec=0.5416watts 0.5416=20 x 4.5=90,so the amount of current is NOT 20 amps V x I=0.5416 I=0.5416/4.5=0.12amp IR=4.5 R=4.5/0.12=37.38ohms
P=1950/3600 joules/sec=0.5416watts 0.5416=20 x 4.5=90,so the amount of current is NOT 20 amps V x I=0.5416 I=0.5416/4.5=0.12amp IR=4.5 R=4.5/0.12=37.38ohms
