Electricity Flashcards
3 types of charge
Electron, proton, neutron
Charge on 1 electron
1.6 X 10^-19
Is water a good conductor?
Pure water (distilled water)- insulator
Impure or tap water- conductor
Charge is denoted by which letter?
Q
How to find charge?
Q=n*e
[(e)=1.6X10^-19]
How to find charge?
Q=n*e
[(e)=1.6X10^-19]
Number of electrons in one coulomb of charge
6.25 X 10^18
What is electric current?
Rate of flow of electric charges in a conductor
Current is denoted by which letter?
I
SI Unit of charge
Coulomb
SI unit of current
Ampere
Equation to find current
I(ampere)=Q(coulomb)/t(seconds)
Ampere can also be written as?
Coulomb/second
What is 1 ampere?
When 1 coulomb charge flows in 1 second in a conductor, then the current is said to be 1 ampere.
What is Ammeter?
An instrument to record and measure electric current.
Always connected in series.
What is galvanometer?
An instrument for measuring small electric currents.
What is potential difference?
Amount of work done in moving unit positive charge from a region of high concentration to low concentration in an electric field.
Potential difference is also called as?
Voltage
SI unit of potential difference
Volt
What is voltmeter?
An instrument for measuring the potential difference between 2 points in an electric circuit.
Potential difference is denoted through which letter?
V
Equation to find V?
V=W/Q
[(W)= Work done]
[(Q)= Charge]
Ohm’s law
Current flowing through a conductor is directly proportional to the potential difference applied across the ends of the conductor, at a particular temperature.
Equation of ohm’s law
V directly proportional to I
By adding a constant
V=IR
[(R)=resistance]
What is resistance?
Property of a conductor due to which a it opposes the flow of current through it.
Resistance is denoted by which letter?
R
SI unit of resistance
Ohm
What is 1 ohm?
If 1 ampere of current flows through the conductor when a potential difference of 1 volt is being applied it, the resistance is said to be 1 ohm.
Equation to find resistance
R=V/I
Factors affecting resistance
Length
Area of cross section
Nature of material
Temperature
What is an ohmmeter?
A device used for measuring resistance.
What is resistivity?
Resistance of that material of unit length and unit cross-sectional area.
Factors affecting resistivity?
Resistivity remains same always.
The resistance of a conductor is directly proportional to?
It’s length
R proportional to L
[(L)=LENGTH]
Resistance of a conductor is inversely proportional to?
It’s area of cross-section.
R proportional to L/A
[(A)= Area of cross-section]
To make R equal to L/A, we add which constant?
Rho.
R=RhoL/A
Rho=RA/L
Series circuit
Charge remains same throughout all resistors.
Voltage gets divided.
Parallel circuit
Voltage remains the same.
Charge is divided inversely proportional to the resistance.
Potential difference and resistance in series circuit.
V=V1+V2+V3……
V1= IR1
V2= IR2
V3= IR3
IR= IR1+IR2+IR3
R(net)= R1+R2+R3
Potential difference and resistance in parallel circuit.
I=I1+I2+I3
I1=V/R1
I2=V/R2
I3=V/R3
V/R(net)= V/R1+V/R2+V/R3
1/R(net)= 1/R1+1/R2+1/R3
Effects of current
Chemical effects of current.
Magnetic effects of current.
Heating effects of current.
Joule’s law of heating
Heat generated in a conductor is directly linked to the square of current, resistance and the time period of the current flow.
Equation of joule’s law of heating.
H= I^2RT
Element used in the filament of the bulb
Tungsten
The coils in a heater are made of?
Nichrome
Electric Power
The rate at which electric energy is dissipated or consumed in an electric circuit.
General equation to find power
P= V*I
Another general equation to find power
P= W/T
Equation to find power in a series circuit
P= I^2R
Equation to find power in a parallel circuit
P= V^2/R
SI unit of power
WATT
1 watt
The power consumed by a device that carries 1 ampere of current when operated at a potential difference of 1 volt.
A single term for 1000 watts
1 kilowatt
Electric energy
Energy consumed by an electric circuit to flow current through it is referred to as electrical energy.
Commercial unit of energy
Kwh
1 Wh (watt hour)
Energy consumed when 1 watt of power is used for 1 hour.
