Electricity 1 Flashcards
(56 cards)
What is current in electricity?
Current is the rate of flow of charge, measured in amperes (A).
Current is defined as the amount of charge in coulombs flowing per second.
What is the unit of charge?
The coulomb (C) is the unit of charge.
The elementary charge, e, is approximately 1.60 × 10^-19 C.
How can you measure the current in a circuit?
You can measure the current using an ammeter.
The symbol for an ammeter is ‘A’.
What charge do electrons carry?
Electrons carry a charge of -e, where e is the elementary charge.
Protons carry an opposite charge of +e.
What is potential difference (p.d.)?
Potential difference is defined as the work done per unit charge moved.
The formula is V = W/Q, where W is work done in joules and Q is charge in coulombs.
What defines 1 volt?
1 volt (V) is defined as the potential difference when 1 joule of work is done moving 1 coulomb of charge.
Therefore, 1 V = 1 J/C.
How is potential difference measured?
The potential difference across a component is measured using a voltmeter.
The symbol for a voltmeter is ‘V’.
What happens when a charged particle is accelerated by a potential difference?
The energy transferred is equal to the work done on the particle, W = VQ.
For an electron, this can be expressed as W = Ve.
What is the formula for current in terms of drift velocity?
The current is given by I = Anev, where A is the area, n is the number density of electrons, and v is the drift velocity.
This equation indicates how current depends on the number of charge carriers and their motion.
What are charge carriers in metals?
In metals, the charge carriers are free electrons.
These electrons come from the outer shell of each atom.
What is an electrolyte?
An electrolyte is a substance containing ions that conducts electricity.
Examples include solutions like sodium chloride in water.
What happens to gases under high voltage?
Gases can become conductive if a high enough voltage is applied, resulting in ionization.
This can lead to the formation of a spark as electrons are ripped from atoms.
Fill in the blank: The potential difference across components in parallel is ______.
the same.
This means that voltmeters should be connected in parallel with the component being measured.
True or False: The maximum value that a voltmeter can measure is called the full scale deflection.
True.
This term refers to the highest voltage the voltmeter can accurately measure.
What is the relationship between the number of charge carriers and current?
If you double the number of charge carriers, the current doubles.
This is due to the increased flow of charge through the conductor.
What is the formula for kinetic energy gained by an electron?
Kinetic energy = ½mv², where m is the mass of the electron and v is its velocity.
The energy transferred to the electron is equal to the work done to accelerate it.
What is the difference between resistance and resistivity?
Resistance is a property of a component, while resistivity is a material property.
What is the unit of resistance?
Ohms (Ω)
What determines the resistance of a wire?
Resistance depends on:
* Length
* Cross-sectional area
* Resistivity of the material
What happens to resistance as the length of a wire increases?
The resistance increases.
How does the cross-sectional area of a wire affect resistance?
A larger cross-sectional area decreases resistance.
What does resistivity depend on?
Resistivity depends on:
* Material of the wire
* Environmental factors (e.g., temperature)
What is the symbol for resistivity?
ρ (rho)
What is the resistivity of a material defined as?
The resistance of a 1 m length with a 1 m² cross-sectional area.
