Physics 2.1.6 Flashcards
Ohm’s Law States that:
The Current through a Conductor is Directly Proportional to the Potential Difference across it.
What do you call Electrical Conductors that obey Ohm’s Law?
Ohmic Conductors.
What are Ohmic Conductors?
Electrical Conductors that obey Ohm’s Law.
3 Common Examples of Ohmic Conductors: (3)
-Fixed Resistors.
-Wires.
-Heating Elements.
Which Equation represents Ohm’s Law?
V = IR
Ohm’s Law is relevant only at…
Constant Temperatures.
What type of Conductor are Filament Lamps?
Non-Ohmic.
What is a ‘Non-Ohmic’ Conductor?
An Electric Conductor where the Current and PD are not Directly Proportional.
Why are Filament Lamps Non-Ohmic Conductors?
Because the Resistance of the Filament Lamp Increases as the Temp. of the Filament Increases.
What is an I-V Graph?
A Graph that shows the relation between Current & PD in a Circuit.
What does the I-V Graph for an Ohmic Conductor look like?
A Straight Line that goes through the Origin.
What does the I-V Graph for a Filament Lamp show?
It shows the Current Increasing at a Proportionally Slower Rate than the PD.
Why does Current Increase at a Proportionally Slower Rate than the PD in a Filament Lamp? (4)
-As the Current Increases, the Temp. of the Filament in the Lamp Increases.
-The Higher Temp. causes the Atoms in the Metal Lattice of the Filament to Vibrate more,
-This causes an Increase in Resistance, as it becomes more difficult for free Electrons (the Current) to pass through.
-Resistance opposes the Current, causing the Current to Increase at a Slower Rate.
All Solids are made up of ___ Atoms.
Vibrating.
The Higher the Temp. of an Object, the Faster the Atoms will ___.
Vibrate.
What happens to the Electric Current through an Object when the Object is Heated up? (4)
-As you Heat up the Object, Atoms will Vibrate more & more.
-Free Electrons (Current) will collide with these Atoms, which impeded their flow.
-Current Decreases.
-Resistance Increases.
What type of Conductor are Diodes?
Non-Ohmic.
What do Diodes do, and what is it called?
Diodes only allow Current to flow in one Direction only. This is called Forward Bias.
Explain the Reverse Direction of Diodes, and give the name.
In the Reverse Direction, the Diode has very High Resistance, and therefore no Current Flows. This is Called Reverse Bias.
In the I-V Graph for a Diode, when the Current is in the Direction of the arrowhead Symbol, it is…
Forward Bias.
When the Diode is switched around, it is called…
Reverse Bias.
Circuit Element I-V Graphs can be either ___ or ___-___.
Linear, Non-Linear.
What type of I-V Graph do Circuit Elements that obey Ohm’s Law have?
Linear.
What type of I-V Graph do Circuit Elements that do not obey Ohm’s Law have?
Non-Linear.
Electric Circuit Elements that have Linear I-V Graphs (Components that obey Ohm’s Law) include: (3)
-Fixed Resistors.
-Wires.
-Heating Elements.
Electric Circuit Elements that have Non-Linear I-V Graphs (Components that do not obey Ohm’s Law) include: (4)
-Filament Lamps.
-Diodes & LEDs.
-LDRs.
-Thermistors.
