Unit 8 Science Flashcards
What is the SI unit for potential difference?
volts (V)
Similar charges tend to ____________ one another.
repel
What happens to an atom that loses electrons?
It becomes positively charged.
What tends to resist the flow of electric charges?
insulator
What is the SI unit for current?
ampere (A)
What are the two types of current?
Alternating and Direct
What is the symbol for electric current?
I
Opposite charges tend to ____________ one another.
attract
What is the rate that electric charges move through a wire in a single direction?
electric current
What happens to an atom that gains electrons?
It becomes negatively charged.
A resistor has a resistance of 120 Ω. How much current is in the resistor if there is a potential difference of 12.0 V across the resistor? [I=V/R]
0.10 A
A set of electric trains are powered by a 9 V battery. What is the resistance of the trains if they draw 4.0 A of current? [I=V/R]
2.3 Ω
A 13 Ω resistor has 0.050 A of current in it. What is the potential difference across the resistor? [I=V/R]
0.65 V
The SI unit of resistance is the
ohm
Objects become charged when _________ are moved from one object to another.
electrons
Positively charged objects have _____ positive than negative charges.
more
Negatively charged objects have _____ positive than negative charges.
less
Neutral objects have ______ positive than negative charges.
equal
A substance that resists the flow of electrons or electrical charge.
insulator
A substance that allows electrons (or electric charge) to easily flow through it.
conductor
Ohm’s Law Formula
I = V/R
Current = Voltage/Resistance
In an electrical field, the resistance is 2 Ω and the current is 4 A. What is the voltage?
I = V/R
Current = Voltage/Resistance
Voltage = 8 V
A refrigerator receives 240 V of electricity. If it uses 32 A of current, what is the resistance of the refrigerator?
I = V/R
Current = Voltage/Resistance
Resistance = 7.5 Ω
What is the voltage across a 75 Ω resistor with 1.5 A of current?
I = V/R
Current = Voltage/Resistance
Voltage = 112.5 V
In a simple series circuit, why does the bulb light up when you close the switch?
The bulb lights up when the switch is closed because it creates a closed path for electrons to flow through.
In a simple series circuit, why does the bulb go out when you open the switch?
The bulb stops lighting up with an opened switch, as there is no longer a path of electron flow.
Define electric circuit.
An electric circuit is a path that electrons flow through.
What happens to the electric current in a series circuit when voltage decreases?
electric current decreases
What happens to the electric current in a series circuit when voltage increases?
electric current increases
What happens to the electric current in a series circuit when resistance increases?
electric current decreases
What happens to the electric current in a series circuit when resistance decreases?
electric current increases
Describe a parallel circuit.
A parallel circuit contains two or more paths for current to flow through.
In a parallel circuit containing 3 light bulbs, what happens to the other two bulbs when one goes out?
The other two bulbs will not go out.
In a parallel circuit, the total current is equal to _____________
the sum of the current in each path.
In a parallel circuit, voltage is (same/different) across each component.
same
The total resistance is (less/more) than the resistance of one resistor alone.
less
The bulbs in a (parallel/series) circuit are brighter than bulbs in a (parallel/series) circuit.
parallel, series
The battery life is typically shorter in a (parallel/series) circuit when compared to (parallel/series) circuits.
parallel, series
