kirchoff’s Law, resistivity

what is Kirchhoff’s first law

Total charge into the junction is equal to the charge out of the junction (charge is conserved)

What is Kirchhoff’s second law

Total energy into a junction is equal to energy out of the junction

How can u apply Kirchhoff’s first law to a circuit question

I (in) = I (out) - as first law is that charge is conserved and Q=It so I (in) change in time = I (out) change in time and if you considered it as one second you get I (in) = I (out)

How can u apply Kirchhoff’s second law to a circuit question

Sum of EMFs = Sum of PD - as second law is that energy is conserved and E=VQ so V(in) x Q = V (out) x Q and if you considered it as per unit of charge you get V (in) = V (out), since EMF = V1 + V2 + V3….. sum of EMFs is equal to sum of PDs

What is the equation to find total resistance in a parallel circuit where the resistors are identical

R(T) = Resistance/ number of resistors

What is the equation to find total resistance in a parallel circuit where the resistors are non-identical

1/Rt = 1/R1 + 1/R2 + 1/R3…

What is resistivity

A fundamental property of a material (independent of shape and size)

What are the units for resistivity

Ohm-metre

What does resistivity depend on

Material composition and temperature

Do good electrical conductors have high resistivity

No

Do insulators have high resistivity

Yes

What is the word equation for resistivity

Resistance = resistivity x length/ area

What is the symbol equation for resistivity

R=\frac{\rho L}{A}

What is resistance

How much a specific component opposes the flow of electric current

What is resistance defined as

The ratio of voltage to current in a circuit

What does resistance depend on

Length, cross-sectional area and resistivity of the material

What are the units for resistance

ohms

What is voltage

The force that pushes the electrons, for electrons to move there must be a “voltage/potential difference”

When is current not split across in a parallel circuit

When there is a short circuit (a pathway with no resistance), all current passes through it