Voltage Flashcards
What is the relationship between voltage, energy, and charge, mathematically expressed?
V= E/Q, where V is voltage, E is energy, and Q is charge.
What is voltage?
Voltage is a measure of the amount of energy the a battery gives to separated charges (electrons).
What is one electron volt (eV) equal to in joules?
1eV= 1.6 x 10^-19 joules.
What device is used to measure voltage?
A voltmeter.
What is potential difference/voltage drop?
Potential difference/voltage drop is the amount of electrical potential energy lost by each coulomb of charge at a given part of a circuit, measured in joules.
How do voltmeters work?
Voltmeters measure voltage drop, by being plugged into two points of the circuit in parallel. A voltmeter measures the difference of voltage at the two points.
How can the amount of energy transformed by a charge passing through a load be expressed as?
E= QV, where E is energy, Q is charge, and V is voltage.
How can the amount of charge passing through a load in a time interval be expressed as?
Since Q=It (where t is time in seconds and I is current), E = VIt.
What is power?
Power is the rate of doing work, or the rate or which energy is transformed from one form to another.
What is the derivation for the formula P=VI?
Power is equal to the amount of energy transformed per second, therefore P=E/t. Since E=VIt, P= VIt/t. This is simplified to P(power)=V(voltage)I(current).
What is electromotive force?
Electromotive force (emf) is a measure of the energy supplied to a circuit for each coulomb of charge passing through the power supply. The unit for emf is volts.
What is the formula for finding the amount of energy supplied to the charge passing through the power supply?
E=ℰQ, or E=ℰIt
What is the formula for the power delivered to the charge passing through the power supply?
Since I=E/t, P=ℰI.
