Typically, you will get current to flow as long as it has a path with finite resistance (
even zero
), a voltage difference, and a supply of charge carriers (e.g., electrons).
The relationship between current, voltage and resistance is expressed by
Ohm’s Law
. This states that the current flowing in a circuit is directly proportional to the applied voltage and inversely proportional to the resistance of the circuit, provided the temperature remains constant.
What conditions are needed for current to flow?
To produce an electric current, three things are needed:
a supply of electric charges (electrons) which are free to flow
, some form of push to move the charges through the circuit and a pathway to carry the charges. The pathway to carry the charges is usually a copper wire.
What happens to current if resistance increases?
In other words, for a given voltage, the
current in the circuit will decrease as the resistance increases
. Mathematically, Ohms Law is: I = E/R, or current equals voltage divided by resistance. This simple equation can be transformed to find voltage or resistance, given the other two quantities.
Can current flow through resistance?
The
current is the same through each resistor
. The total resistance of the circuit is found by simply adding up the resistance values of the individual resistors: … A series circuit is shown in the diagram above. The current flows through each resistor in turn.
Can current flow without a source?
Voltage is the Cause, Current is the Effect
Voltage attempts to make a current flow, and current will flow if the circuit is complete. … It is possible to have voltage without current, but
current cannot flow without voltage
.
How can a continuous flow of current be obtained?
How can we get the continuous flow of electric current? We can get the continuous flow of electric current by
maintaining the potential difference between the two ends of the conductor using a cell or a battery
. It is used to measure the electric current in the circuit. It is connected in series with the resistance.
Is potential difference required for current flow in a wire?
Without potential difference
, current can not flow because we know that an electric current flows between two points due to the potential difference between them. … This flow of electric charges in a conductor (metal wire) is called electric current.
Is current directly proportional to resistance?
The current in a circuit is directly proportional to
the electric potential difference impressed
across its ends and inversely proportional to the total resistance offered by the external circuit. … And the greater the resistance, the less the current.
How do I calculate resistance?
If you know the total current and the voltage across the whole circuit, you can find the total resistance using Ohm’s Law:
R = V / I
. For example, a parallel circuit has a voltage of 9 volts and total current of 3 amps. The total resistance R
T
= 9 volts / 3 amps = 3 Ω.
What are the 3 forms of Ohms law?
3-4: A circle diagram to help in memorizing the Ohm’s Law formulas
V = IR, I = V/R, and R= V/I
. The V is always at the top.
What happens to current when resistance decreases?
The relationship between Voltage, Current and Resistance forms the basis of Ohm’s law. … Likewise, if we increase the resistance, the current goes down for a given voltage and if we
decrease the resistance the current goes up
.
Which changes would cause an increase in the resistance?
Answer: Resistance can
increase relative to Temperature, Nature of Material, Length of Conductor or wire
.,and Cross-section area.
What is difference between resistance and resistivity?
Resistance is the physical property of a substance because of which it opposes the flow of current i.e.
electrons
. Resistivity is the physical property of a particular substance which is having particular dimensions.
Does current flow when voltage is zero?
If you have ZERO volts then
you don’t have a voltage therefore you have no current
. The ohms law you quoted is not applicable for ZERO volts. When you DO have current flow, then SOMEWHERE there is a voltage that is not ZERO.
What happens if there is no current?
When there is no current in the wire, their is
no magnetic induction
. … The moment we allow a current to flow through, there is a magnetic induction and thus we get an electromagnet.
