chap 7 chap stick current Flashcards
What is a galvanometer
Used to detect very small electric currents
What is electric current defined as
Rate of flow of electric charges through a conductor
How to measure electric current & SI unit
Ammeter
ampere (A)
What is voltage
Potential difference between two points
How is voltage measure + SI Unit
Voltmeter
volt (v)
In what circuit are Ammeter and Voltmeter connected respectively
A - Series
V - Parallel
Why is Ammeter connected in Series and Voltmeter in Parallel
A - To get the full current flowing through a branch
V- objects in parallel experience the same potential difference
What is resistance
Ability of a conductor to limit or resist the flow of electric current
What is the SI unit for resistance & what are types of resistor
Ohm
Fixed resistor (cannot be adjusted)
Variable resistor / rheostat (can be adjusted)
Where is rheostat used in
Radio / TV
What is the relation between current, voltage and resistance
Ohm’s Law (V=IR)
What does Ohm’s Law state
Electric current -> directly proportional -> Voltage across two ends of the conductor
Provided temperature & other physical situations remain unchanged
How does battery work
Terminal neg - excess neg
Terminal pos - lack neg
Causes potential difference & energy that pushes electron from neg -> pos
After some time, potential diff will lessen and battery dies
What is a series circuit
Made up of electrical components - connected one after another,
Current flows through single path
What is a parallel circuit
Separated into several diff parts of electrical circuit
Each parallel path has electrical components
How is current, voltage and resistance in series
I = I1 = I2
V = V1 + V2
R = R1 + R2
Advantage of series
Every component receives same amount of current
Every component controlled by same switch
Increase voltage supplied more current
Disadvange of series
One electrical appliances is damaged -> others cease to function
Adding more -> increase resistance & decrease current
Cannot be switched off individually
How is current, voltage and resistance in Parallel
I = I1 + I2
V = V1 = V2
1/R = 1/R1 + 1/R2
Advantage of parallel
Can be switched on or off separately
Increase of electrical appliance does not affect function of other appliances
Disadvantage of parallel
Voltage cannot be adjusted because is the same as the source of voltage
In a house, is series or parallel used? How is the main power supply controlled
Parallel
Distrubution panel
What is direction of electron flow & current flow
Electron: Neg -> Pos
Current: Pos -> neg
