Electricity Flashcards
Define electric charge
Electric charge= electric current x time
Q=It
Q=AS (Coloumb)
I=A
t=s
Give another formula for electric charge
Electric charge=number of charged particles x charge on each particle
Q=Nq
Q=As (Coloumb)
N=no unit
q=Coloumb
Q=nAlq
n= number density
A=Area
l=length
q=charge on each carrier
What is the value of elementary charge?
e is elementary charge and its value is 1.6x10-19 C.
C is coloumbs
What is the charge of an electron, positron or proton particle?
If each particle is electron, positron or proton they have same charge which is equal to elementary charge.
Charge on electron=-e
Charge on positron=charge on proton=+e
What is the formula for charge density or number density?
Number Density=number of charged carriers/volume
n=N/V
n=m^-3 (per meter cube)
N=no units
V=m^3
What is the function of number density?
Number density describes how good or bad a conductor is.
Higher the number density better is the conductor.
What is another name for charged carriers?
Charged carriers are also called free electrons, delocalised electrons. These electrons can easily slip on the lattice of metal crystals formed by layers of metal particles.
What is drift velocity?
Speed at which charge carriers are drifting through conductor is called drift velocity.
Drift velocity=Distance moved by charged carrier/time taken
Vd=l/t
What is a conductor?
A conductor is anything that transfers charge from one point to another.
What is drift?
The motion of charged carriers (electrons) through a conductor is called drift.
What is the relationship between drift velocity and current.
Vd∝I
I=Current
Vd=drift velocity
Important for deriving formula
What is the relationship between Drift Velocity and cross sectional area of a conductor?
Vd∝1/A
A=cross sectional area of a conductor
Vd=drift velocity
Imporatnt for deriving formula
What is the relationship between number density and drift velocity?
Vd∝1/n
Vd=drift velocity and n=number density
Imporant for deriving formula
What is the relationship between charge on each carrier and drift velocity?
Vd∝1/q
Vd=drift velocity
q=charged carrier
Imporatnt for deriving formula
What factors affect drift velocity and what formula can we derive from their relationship?
Current
Cross sectional area of a conductor
Number density
Charge on each carrier
If it is the same conductor all the above variable will stay the same.
Vd=I/AnQ
What is the formula of a prism?
also volume of a cyllinder
Volume of a prism=Base area x height
V=Al
A=area
L=height
Volume of a cylinder=1/4 x π d^2 h
What is the formula of the area of circular wires?
A=πd^2/4
therefore Vd=4I/πd^2nq
What is current?
Current is the flow of charge. Role of current in a circuit is to pick up and drop off energy. Current does not get consumed. Symbol for current is I. Unit for current is ampere. Current is a scalar quantity.