Atomic Structure & Charging
What are the three particles that make up an atom and what are their charges?
Protons (+), Electrons (–), Neutrons (0)
Which force is stronger: gravitational or electrostatic?
Electrostatic Force
🎯 DAILY DOUBLE
What is required for charge to flow in a circuit?
A potential difference (voltage)
In a series circuit, what stays constant?
Current
What stays constant in a parallel circuit?
Voltage
How do like poles react?
How do opposite poles react?
Like - Repel
Opposite - Attract
Explain the difference between a conductor and an insulator in terms of electron movement.
A conductor allows electrons to move freely and charges spread evenly.
An insulator does not allow electrons to move freely and charges stay localized.
If one charge is doubled, what happens to the force?
If both charges are doubled?
One doubled → Force doubles
Both doubled → Force quadruples
State Ohm’s Law and define each variable.
I = V / R
I = current (A)
V = voltage (V)
R = resistance (Ω)
How do you calculate total resistance in series?
RT = R1 + R2 + R3…
🎯 DAILY DOUBLE
Where is a voltmeter placed? Where is an ammeter placed? Why?
Voltmeter: Parallel (measures potential difference across component)
Ammeter: Series (measures current flowing through circuit)
Where is magnetic force strongest?
At the poles
🎯 DAILY DOUBLE
A negatively charged rod touches a neutral metal sphere.
What charging method occurs?
What is the final charge of the sphere?
Conduction
Negative (electrons transfer through contact)
Two charges are 3 m apart. If the distance is cut in half, how does the force change?
Force increases by a factor of 4
A 6Ω resistor has 3A flowing through it. What is the voltage?
V = IR
V = (3)(6) = 18V
Three 10Ω resistors in series.
What is total resistance?
30Ω
How is total resistance calculated in parallel?
1/RT = 1/R1 + 1/R2 + 1/R3…
How do you make an electromagnet?
Wrap a coil of wire around an iron core and connect it to a voltage source.
Two objects attract each other.
What are the two possible charge situations?
Opposite charges
OR
One neutral and one charged
🎯 DAILY DOUBLE
State Coulomb’s Law in words.
The electrostatic force is directly proportional to the product of the charges and inversely proportional to the square of the distance between them.
What is required for charges to flow in a circuit?
Potential difference (Voltage)
If one bulb burns out in a series circuit, what happens to the rest?
All bulbs go out because the circuit is open and current stops.
Three 10Ω resistors in parallel. What is total resistance?
RT = 3.33Ω
How can a permanent magnet become demagnetized?
Dropping it
Heating it
Disrupting domain alignment
A positively charged rod is brought near (but does not touch) a neutral object.
What charging method is occurring?
Are electrons transferred?
Induction
No electrons are transferred
Two charges are 3 m apart. If the distance is cut in half, how does the force change?
Force increases by a factor of 4
A circuit has 12V and 4Ω resistance.
What is the current?
What is the power?
I = V/R = 12/4 = 3A
P = IV = (3)(12) = 36W
🎯 DAILY DOUBLE
Why does total resistance increase when resistors are added in series?
Because each resistor adds opposition to current in the same single path.
If one branch in a parallel circuit breaks, what happens to the others?
The other branches continue to function because current has multiple paths.
🎯 DAILY DOUBLE
What is the difference between a motor and a generator?
Generator: Mechanical → Electrical
Motor: Electrical → Mechanical
Why does a charged object always attract a neutral object?
Because the charged object causes charge separation (polarization) in the neutral object, creating opposite charges on the near side and producing attraction.
If distance is cut in half AND one charge is doubled, how does force change overall?
Distance halved → force ×4
Charge doubled → force ×2
Total change → force increases by factor of 8
If resistance increases while voltage stays constant, what happens to current? Explain using formula.
Current decreases because I = V/R. As R increases, I decreases.
A 9V battery is connected to three 3Ω resistors in series.
Total resistance?
Current?
RT = 9Ω
I = 9/9 = 1A
Why does total resistance decrease when more resistors are added in parallel?
Because additional branches provide more paths for current, reducing overall resistance.
Name 3 ways to increase the strength of an electromagnet.
Increase coils
Increase voltage
Use iron core