Electrical Characteristics
Atoms with imbalance in its charge, can be negatively- or positively-charged
Ions
What happens if two negatively-charged ions come together?
Potential difference is another name for what?
Voltage
Dynamic electricity
When a plastic comb is passed through dry hair, the charge acquired by the comb is
Always negative, as it accumulates electrons
What is the characteristic of a particle that has more protons than electrons?
Positively-charged
Find the current I through a resistor of resistance R = 2 Ω if the voltage across the resistor is 6 V.
I = 6 / 2 = 3 A
What is the name of an electrical circuit in which the current flows through two or more separate paths?
Parallel circuit
A bird comes and sits on a bare high power line. It will...
not be affected practically
Two charges 3×10-5 and 5×104 are placed at a distance 10cm from each other. Find the value of electrostatic force acting between them.
13.5×1011
A series circuit has two resistors R1 and R2 that have resistances of 5 Ω and 10 Ω, respectively. The voltage across resistor R1 is equal to 4 V.
Find the current passing through resistor R2!
A series circuit has the same current going through each resistor.
I1 = 4 / 5 = 0.8 A
V2 = R2 I2 = 10 (0.8) = 8 V
What is the other name for batteries in a circuit?
Cells
Any material that can conduct electricity with no resistance because of special treatments
Superconductor
Charge on a body which carries 200 excess electrons is...
q = n.e = 200 x (-1.6 x 10-19) = -3.2 x 10-17 C
In a circuit, the potential drop across the 10 kΩ -resistor is 100 V. What is the current through the resistor?
100 V / 10,000 Ω = 0.01 A
In a simple series circuit, why does the bulb light when you close the switch?
Because closing the switch completes the circuit
Materials that tightly hold on to their electrons are considered
A plastic piece rubbed with wool is found to have a negative charge of 3×10−7 C.
Estimate the number of electrons transferred
q=3×10−7 C
e=1.6×10−19 C
Quantization of charge, q=ne
n= e / q
n=1.875×1012 electrons
Two circuits have the same electrical current in milliamperes.
The first one has 120 V of voltage and 100 Ω of resistance, the second one has 24 V of voltage and one resistor.
Find the resistance in the second circuit in mΩ!
24 / 1,200 x 10-3 = 20,000 mΩ
Why are homes not wired in series circuits?
If you turn off one appliance, the rest will turn off.