This relationship results in an equivalent resistance
${R}_{\text{eq}}$ that is less than the smallest of the individual resistances. When resistors are connected in parallel, more current flows from the source than would flow for any of them individually, so the total resistance is lower.
Analysis of a parallel circuit
Three resistors
${R}_{1}=1.00\phantom{\rule{0.2em}{0ex}}\text{\Omega},{R}_{2}=2.00\phantom{\rule{0.2em}{0ex}}\text{\Omega},$ and
${R}_{3}=2.00\phantom{\rule{0.2em}{0ex}}\text{\Omega},$ are connected in parallel. The parallel connection is attached to a
$V=3.00\phantom{\rule{0.2em}{0ex}}\text{V}$ voltage source. (a) What is the equivalent resistance? (b) Find the current supplied by the source to the parallel circuit. (c) Calculate the currents in each resistor and show that these add together to equal the current output of the source. (d) Calculate the power dissipated by each resistor. (e) Find the power output of the source and show that it equals the total power dissipated by the resistors.
Strategy
(a) The total resistance for a parallel combination of resistors is found using
${R}_{\text{eq}}={\left({\displaystyle \sum _{i}\frac{1}{{R}_{i}}}\right)}^{\mathrm{-1}}$ .
(Note that in these calculations, each intermediate answer is shown with an extra digit.)
(b) The current supplied by the source can be found from Ohm’s law, substituting
${R}_{\text{eq}}$ for the total resistance
$I=\frac{V}{{R}_{\text{eq}}}.$
(c) The individual currents are easily calculated from Ohm’s law
$\left({I}_{i}=\frac{{V}_{i}}{{R}_{i}}\right)$ , since each resistor gets the full voltage. The total current is the sum of the individual currents:
$I={\displaystyle \sum _{i}{I}_{i}}.$
(d) The power dissipated by each resistor can be found using any of the equations relating power to current, voltage, and resistance, since all three are known. Let us use
${P}_{i}={V}^{2}\text{/}{R}_{i},$ since each resistor gets full voltage.
(e) The total power can also be calculated in several ways, use
$P=IV$ .
Solution
The total resistance for a parallel combination of resistors is found using
[link] . Entering known values gives
The total resistance with the correct number of significant digits is
${R}_{\text{eq}}=0.50\phantom{\rule{0.2em}{0ex}}\text{\Omega}.$ As predicted,
${R}_{\text{eq}}$ is less than the smallest individual resistance.
The total current can be found from Ohm’s law, substituting
${R}_{\text{eq}}$ for the total resistance. This gives
Current
I for each device is much larger than for the same devices connected in series (see the previous example). A circuit with parallel connections has a smaller total resistance than the resistors connected in series.
The individual currents are easily calculated from Ohm’s law, since each resistor gets the full voltage. Thus,
The power dissipated by each resistor can be found using any of the equations relating power to current, voltage, and resistance, since all three are known. Let us use
$P={V}^{2}\text{/}R,$ since each resistor gets full voltage. Thus,
Its state that "energy can neither be created nor destroyed but can be transformed from one form to another. "
Ayodamola
what about the other laws
can anyone here help with it please
Sandy
The second law of thermodynamics states that the entropy of any isolated system always increases. The third law of thermodynamics states that the entropy of a system approaches a constant value as the temperature approaches absolute zero.
sahil
The first law is very simple to understand by its equation.
The law states that "total energy in thermodynamic sytem is always constant"
i.e d¶=du+dw where
d¶=total heat
du=internal energy
dw=workdone...
PLEASE REFER TO THE BOOKS FOR MORE UNDERSTANDING OF THE CONCEPT.
it means that the total charge of a body will always be the integral multiples of basic unit charge ( e )
q = ne
n : no of electrons or protons
e : basic unit charge
1e = 1.602×10^-19
Riya
is the time quantized ? how ?
Mehmet
What do you meanby the statement,"Is the time quantized"
Mayowa
Can you give an explanation.
Mayowa
there are some comment on the time -quantized..
Mehmet
time is integer of the planck time, discrete..
Mehmet
planck time is travel in planck lenght of light..
Mehmet
it's says that charges does not occur in continuous form rather they are integral multiple of the elementary charge of an electron.
Tamoghna
it is just like bohr's theory.
Which was angular momentum of electron is intral multiple of h/2π
The properties of a system during a reversible constant pressure non-flow process at P= 1.6bar, changes from constant volume of 0.3m³/kg at 20°C to a volume of 0.55m³/kg at 260°C. its constant pressure process is 3.205KJ/kg°C
Determine: 1. Heat added, Work done, Change in Internal Energy and Change in Enthalpy
this is the energy dissipated(usually in the form of heat energy) in conductors such as wires and coils due to the flow of current against the resistance of the material used in winding the coil.
Henry
it is the work done in moving a charge to a point from infinity against electric field