Ohm’s law states that the voltage (v) across a resistor is directly proportional to the current (i) flowingthrough the resistor, at constant temperature. ie, v α i ,v = iR, where R is the resistance (Ω).
2. State Kirchoff’s Current law.
KCL (Kirchoff’s Current Law) states that the algebraic sum of currents entering a node(or a closed boundary) is zero. (or)The sum of the currents entering a node is equal to the sum of thecurrents leaving the node.
3. State Kirchoff’s Voltage law.
4. An Electric iron is rated 1000W, 240V. Find the current drawn & resistance of the heating element.
P=V2
/R ; R= 2402
/1000 = 57.6Ω and I= V/R =240/57.6 = 4.166 A
5. Define
i) charge
ii) electric current
iii)power
iv) network &
v) circuit.
i) Charge: Charge is an electrical property of the atomic particles of which matter consists, measured incoulombs(C ).
ii) Electric current is the time rate of change of charge, measured in amperes(A). i = dq/dt
A direct current (DC) is a current that remains constant with time.
An alternating current (AC) is a current that varies sinusoidally with time
iii) Power is the time rate of expending or absorbing energy, measured in watts(w). p = dw/dt p- Power
in watts(w); w- energy in joules (J); t - time in seconds (S); (or) p = v i , v - Voltage in volts(V); i - current
in amperes(A);
iv) Network: The inter connection of two or more simple circuit elements forms an electrical network .
v) Circuit : If the network contains at least one closed path, it is an electric circuit.