GENERAL
PHYSICS 2
GENERAL PHYSICS 2
2ND SEMESTER
➢ Use a multimeter to measure V and I;
OHM’S LAW (Ω) to measure current, the meter must be
placed in series.
➢ Ohm’s Law relates voltage, current,
➢ Passive sign convention: If current
and resistance in a resistor. It tells you
enters the positive terminal of an
how much current will flow when a
element, the voltage drop V=(I)(R) is
voltage is applied across a resistor.
positive.
➢ Ohm’s law states that the voltage
across a conductor is directly KIRCHHOFF’S LAW
proportional to the current flowing
through it, provided all physical ➢ Kirchhoff’s laws are two rules based
conditions and temperatures remain on conservation of charge and energy.
constant. They let you analyze complex circuits.
➢ Kirchhoff’s Current Law goes by
WHO WAS GEORG OHM? several names: Kirchhoff’s First Law
and Kirchhoff’s Junction Rule.
● Ohm’s Law is named after Georg According to the Junction rule, the
Simon Ohm, a German physicist who total of the currents in a junction is
published his findings in 1827. equal to the sum of currents outside
the junction in a circuit.
FORMULA: OHM’S LAW
➢ Kirchhoff’s Voltage Law goes by
➢ V = (I)(R) several names: Kirchhoff’s Second
○ V = voltage across the resistor Law and Kirchhoff’s Loop Rule.
(volts, V) According to the loop rule, the sum of
○ I = current through the resistor the voltages around the closed loop is
(amperes, A) equal to null.
○ R = resistance (ohms, Ω)
WHO WAS GUSTAV KIRCHHOFF?
➢ Power related to Ohm’s Law:
● In 1845, a German physicist, Gustav
○ Where P is power in watts (W). Kirchhoff, developed a pair of laws
that deal with the conservation of
IMPORTANT POINTS current and energy within electrical
circuits. These two laws are commonly
➢ Ohm’s Law applies directly to
known as Kirchhoff’s Voltage and
materials/ components that behave
Current Law. These laws help
linearly (called ohmic), e.g., many
calculate the electrical resistance of a
resistors. For non-linear devices
complex network or impedance in the
(diodes, transistors), V and I are not
case of AC and the current flow in
simply proportional.
different network streams. In the next
➢ Units: Voltage = volts (V), Current =
section, let us look at what these laws
amperes (A), Resistance = ohms (Ω).
state.
➢ Conductance G=1/R is another way to
express how easily current flows
(siemens, S).
STEM FIELD 1
, GENERAL CHEMISTRY II
KIRCHHOFF’S CURRENT LAW (KCL) ➢ Choose a loop direction (clockwise or
counterclockwise) and keep sign rules
➢ At any node (junction) in a circuit, the consistent:
sum of currents entering the node ○ If you go from negative to
equals the sum of currents leaving the positive terminal of a source,
node. treat it as a voltage rise (+).
➢ It states that the current flowing into a ○ If you go across a resistor in the
node (or a junction) must be equal to same direction as current, it's a
the current flowing out of it. This is a voltage drop (−) equal to (I)(R).
consequence of charge conservation. ➢ KVL is the basis for mesh (loop)
analysis.
IMPORTANT POINTS
CIRCUIT
➢ KCL follows conservation of charge:
charge does not accumulate at a node ➢ A circuit is a closed conducting path
in steady state. through which electric charges can
➢ Use sign convention: currents entering move. It allows electrical energy from
can be positive and leaving negative a source (battery or power supply) to
(or vice versa); be consistent. be transferred to circuit components
➢ KCL is the basis for nodal analysis such as resistors and capacitors.
(solving voltages at nodes).
FLOW
KIRCHHOFF’S VOLTAGE LAW (KVL)
➢ Electric current is the flow of electric
➢ Around any closed loop in a circuit, charge through a conductor.
the sum of the voltage rises equals the ○ CONVENTIONAL CURRENT
sum of the voltage drops. FLOW
Equivalently, the algebraic sum of all • Direction: positive to
voltages around a loop is zero. negative terminal
➢ It states that in any complete loop • Used in diagrams, laws, and
within a circuit, the sum of all voltages calculations
across components which supply ○ ACTUAL ELECTRON FLOW
electrical energy (such as cells or • Direction: negative to
generators) must equal the sum of all positive terminal
voltages across the other components • Due to movement of
in the same loop. This law is a electrons
consequence of both charge
conservation and the conservation of
energy.
IMPORTANT POINTS
➢ KVL follows energy conservation:
energy gained from sources equals
energy used by circuit elements in a
loop.
STEM XII - ZARA 2
PHYSICS 2
GENERAL PHYSICS 2
2ND SEMESTER
➢ Use a multimeter to measure V and I;
OHM’S LAW (Ω) to measure current, the meter must be
placed in series.
➢ Ohm’s Law relates voltage, current,
➢ Passive sign convention: If current
and resistance in a resistor. It tells you
enters the positive terminal of an
how much current will flow when a
element, the voltage drop V=(I)(R) is
voltage is applied across a resistor.
positive.
➢ Ohm’s law states that the voltage
across a conductor is directly KIRCHHOFF’S LAW
proportional to the current flowing
through it, provided all physical ➢ Kirchhoff’s laws are two rules based
conditions and temperatures remain on conservation of charge and energy.
constant. They let you analyze complex circuits.
➢ Kirchhoff’s Current Law goes by
WHO WAS GEORG OHM? several names: Kirchhoff’s First Law
and Kirchhoff’s Junction Rule.
● Ohm’s Law is named after Georg According to the Junction rule, the
Simon Ohm, a German physicist who total of the currents in a junction is
published his findings in 1827. equal to the sum of currents outside
the junction in a circuit.
FORMULA: OHM’S LAW
➢ Kirchhoff’s Voltage Law goes by
➢ V = (I)(R) several names: Kirchhoff’s Second
○ V = voltage across the resistor Law and Kirchhoff’s Loop Rule.
(volts, V) According to the loop rule, the sum of
○ I = current through the resistor the voltages around the closed loop is
(amperes, A) equal to null.
○ R = resistance (ohms, Ω)
WHO WAS GUSTAV KIRCHHOFF?
➢ Power related to Ohm’s Law:
● In 1845, a German physicist, Gustav
○ Where P is power in watts (W). Kirchhoff, developed a pair of laws
that deal with the conservation of
IMPORTANT POINTS current and energy within electrical
circuits. These two laws are commonly
➢ Ohm’s Law applies directly to
known as Kirchhoff’s Voltage and
materials/ components that behave
Current Law. These laws help
linearly (called ohmic), e.g., many
calculate the electrical resistance of a
resistors. For non-linear devices
complex network or impedance in the
(diodes, transistors), V and I are not
case of AC and the current flow in
simply proportional.
different network streams. In the next
➢ Units: Voltage = volts (V), Current =
section, let us look at what these laws
amperes (A), Resistance = ohms (Ω).
state.
➢ Conductance G=1/R is another way to
express how easily current flows
(siemens, S).
STEM FIELD 1
, GENERAL CHEMISTRY II
KIRCHHOFF’S CURRENT LAW (KCL) ➢ Choose a loop direction (clockwise or
counterclockwise) and keep sign rules
➢ At any node (junction) in a circuit, the consistent:
sum of currents entering the node ○ If you go from negative to
equals the sum of currents leaving the positive terminal of a source,
node. treat it as a voltage rise (+).
➢ It states that the current flowing into a ○ If you go across a resistor in the
node (or a junction) must be equal to same direction as current, it's a
the current flowing out of it. This is a voltage drop (−) equal to (I)(R).
consequence of charge conservation. ➢ KVL is the basis for mesh (loop)
analysis.
IMPORTANT POINTS
CIRCUIT
➢ KCL follows conservation of charge:
charge does not accumulate at a node ➢ A circuit is a closed conducting path
in steady state. through which electric charges can
➢ Use sign convention: currents entering move. It allows electrical energy from
can be positive and leaving negative a source (battery or power supply) to
(or vice versa); be consistent. be transferred to circuit components
➢ KCL is the basis for nodal analysis such as resistors and capacitors.
(solving voltages at nodes).
FLOW
KIRCHHOFF’S VOLTAGE LAW (KVL)
➢ Electric current is the flow of electric
➢ Around any closed loop in a circuit, charge through a conductor.
the sum of the voltage rises equals the ○ CONVENTIONAL CURRENT
sum of the voltage drops. FLOW
Equivalently, the algebraic sum of all • Direction: positive to
voltages around a loop is zero. negative terminal
➢ It states that in any complete loop • Used in diagrams, laws, and
within a circuit, the sum of all voltages calculations
across components which supply ○ ACTUAL ELECTRON FLOW
electrical energy (such as cells or • Direction: negative to
generators) must equal the sum of all positive terminal
voltages across the other components • Due to movement of
in the same loop. This law is a electrons
consequence of both charge
conservation and the conservation of
energy.
IMPORTANT POINTS
➢ KVL follows energy conservation:
energy gained from sources equals
energy used by circuit elements in a
loop.
STEM XII - ZARA 2
