physics 5 Flashcards
What is charge (Q)?
The presence (negative) or absence (positive) of a quantity of electrons on a conducting or insulating surface.
Unit is coulomb (C). 1 Coulomb = 6.24 x10^18 electrons.
What happens when batteries drive electrons onto conducting plates?
It generates a negative charge (Q) if the electrons remain on it.
This is a fundamental principle in battery operation.
Define current (I).
The flow of electrons through a conductor or around a circuit, considered as the rate of change of a charge.
Current flows from high to low potential.
What is the unit of current?
Ampere (Amp).
1 amp = 6.24 x10^18 electrons/s.
Fill in the blank: 1 Coulomb = _______ electrons.
6.24 x10^18
True or False: Current flows from low to high potential.
False
What is the relationship between charge and the number of electrons?
1 Coulomb corresponds to 6.24 x10^18 electrons.
What is voltage also known as?
Potential
Voltage is the driving force for the current.
What is the unit of voltage?
Volt
Voltage is measured in volts.
How is the potential of any point defined?
Voltage above zero referenced to earth
This indicates the potential difference at that point.
What happens to voltage as current flows through a circuit?
A drop in voltage occurs
This is due to the potential difference between two points.
What does electromotive force (EMF) represent?
Voltage delivered by a battery or mains supply
EMF is often represented in circuit diagrams.
What is the formula for energy?
Energy = Voltage (V) x Charge (Q)
Energy is measured in Joules (J).
What is the formula for power?
Power = Voltage (V) x Current (I) = I²R
Power is measured in Watts (W) and represents energy dissipated per unit time.
resistance and ohms law
V(voltage drop)= I(impede current) R (resistance)
