Science hwk?

Question

1. A toaster uses 10 A of current at 120 V. Calculate:
a) the power (in watts) used by the toaster.

b) the energy (in joules) used by the toaster if it is used for 1 minute.

c) the energy (in joules) used by the toaster if it is used for 5 minutes.

2. An electric drill uses a current of 3.5 A. The drill operates on 120 V, what is the drill's power rating?

3. A battery operated radio has a 6 V battery and used 0.1 A of current. What is the power of the radio?

4. A light bulb is rated at 60 W, 120V.
a) How many amperes of current does the bulb require?

b) How much energy does the bulb use if it is used steadily for two hours?

Answer 1

Use P=IV
Energy=Pt

1a. P=10*120=1200 W
1b. E=1200*60=72000 J
1c. E=1200*60*5=360000 J
2 P=3.5*120=420 W
3 P=6*.1=.6 W
4a I=p/v=60/120 =0.5 A
b E=60*2*60*60=432000 J