Joulesto Volts Calculator
Our free other converter handles joulesto volts conversions. See tables, ratios, and examples for quick reference. See charts, tables, and visual results.
Reviewed for accuracy by Manoj Kumar, Mathematics Educator
Joulesto Volts Calculator
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Formula: Voltage (V) = Energy (J) / Charge (C)
Worked example — Voltage = 12 V (12,000 mV)
Formula
Voltage (V) = Energy (J) / Charge (C)
Voltage in volts equals energy in joules divided by electric charge in coulombs. This derives from the definition of the volt: one volt is the potential difference that transfers one joule of energy per coulomb of charge passing through it. Additional relationships include Power = Energy / Time and Current = Voltage / Resistance.
Worked Examples
Example 1: Battery Voltage Calculation
Problem:A battery transfers 240 joules of energy while delivering 20 coulombs of charge. What is the voltage?
Solution:Voltage = Joules / Coulombs V = 240 / 20 = 12 V Millivolts = 12,000 mV Watt-hours = 240 / 3600 = 0.0667 Wh
Result:Voltage = 12 V (12,000 mV)
Example 2: Capacitor Energy to Voltage
Problem:A capacitor stores 50 joules with a charge of 0.5 coulombs. Find the voltage across it.
Solution:Voltage = Joules / Coulombs V = 50 / 0.5 = 100 V kV = 0.1 kV Calories = 50 / 4.184 = 11.95 cal
Result:Voltage = 100 V (0.1 kV)
Frequently Asked Questions
How do you convert joules to volts?
Joules cannot be directly converted to volts because they measure different quantities: joules measure energy and volts measure electric potential. However, if you know the electric charge in coulombs, you can calculate voltage using the formula V = J / C, where V is volts, J is joules, and C is coulombs. This relationship comes from the definition of a volt: one volt is the potential difference that imparts one joule of energy per coulomb of charge. You always need at least two quantities to find the third.
What is the relationship between joules, volts, and coulombs?
These three quantities are linked by the fundamental equation E = V times Q, where E is energy in joules, V is voltage in volts, and Q is charge in coulombs. One joule equals one volt times one coulomb. A 12-volt car battery delivering 100 coulombs of charge transfers 1200 joules of energy. This relationship is essential in circuit design, battery sizing, and understanding how electrical energy is stored and delivered in capacitors and other components.
How are joules related to watts and electrical power?
A watt is defined as one joule per second. Power (watts) equals energy (joules) divided by time (seconds). In electrical circuits, power also equals voltage times current (P = V x I) and voltage squared divided by resistance (P = V^2 / R). If a 100-watt light bulb runs for 60 seconds, it consumes 6000 joules of energy. Understanding these relationships is fundamental for sizing power supplies, calculating energy costs, and designing electrical systems.
What are typical joule values in everyday electrical devices?
A single AA battery stores about 9360 joules (1.5V x 2600mAh x 3600s/h divided by 1000). A fully charged smartphone battery holds roughly 40,000-50,000 joules. A car battery stores about 2.6 million joules. A lightning bolt delivers approximately 1 billion joules. A defibrillator shock uses 200-360 joules. One kilowatt-hour, the standard unit on electricity bills, equals 3.6 million joules. These numbers illustrate the vast range of energy scales in electrical systems.
References
Reviewed for accuracy by Manoj Kumar, Mathematics Educator · Editorial policy
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