Question

1. A 5 Ohm resistor is connected to a 9 Volt battery. How many Joules of thermal energy are produced in 7 minutes?

2. The current in a flashlight powered by 4.5 Volts is 0.5 A. What is the power delivered to the flashlight?

3. If the flashlight in the previous problem is left on for 3 minutes, how much electric energy is delivered to the bulb?

4. A 50 Ohm resistance causes a current of 5 milliamps to flow through a circuit connected to a battery. What is the power in the circuit?

5. How many Joules of electric energy are delivered to a 60 Watt lightbulb if the bulb is left on for 2.5 hours?

Answer 1

Question 1: 189 joules

Question 2: 2.25 watts

Question 3: 405 joules

Question 4: 0.00125 watts

Question 5: 450000 joules

Step-by-step explanation:

question 1:

Volt=1.5v

Resistance =5 ohms

Time=7 minutes

Time=7 x 60

Time=420 seconds

Current =voltage ➗ resistance

Current =1.5 ➗ 5

Current =0.3 amps

Energy=current x voltage x time

Energy=0.3 x 1.5 x 420

Energy =189 joules

Question 2:

Current =0.5 amps

Voltage =4.5v

Power=current x voltage

Power=0.5 x 4.5

Power=2.25 watts

Question 3:

Current=0.5 amps

Voltage=4.5v

Time =3 minutes

Time =3x60

Time =180 seconds

Energy=current x voltage x time

Energy=0.5 x 4.5 x 180

Energy =405 joules

Question 4:

Resistance=50 ohms

Current =5 milliamps

Current =5/1000

Current =0.005 amps

Power =current x current x resistance

Power=0.005 x 0.005 x 50

Power=0.00125 watts

Question 5:

Power =50 watts

Time=2.5 hour

Time=2.5 x 60 x 60

Time =9000 seconds

Energy=power x time

Energy=50x9000

Energy=450000 joules