P5 Flashcards
SCI unit for Power. [1]
W or Watt
SCI unit for energy. [1]
J or Joules
SCI unit for Current. [1]
A or Ampere
SCI Unit for Charge. [1]
C or Coulums
SCI Unit for Potential Difference. [1]
V or Volt
SCI Unit for Electro Motive Force. [1]
V or Volt
What are conductors, give some examples. [2]
Materials that Allow electric current to go through because they have free electron/delocalised electrons.
Examples -
Metal : Copper, Iron
Non-Metal : Graphite, graphine
What are Insulators, give some examples. [2]
They do not allow electric current o thorugh because they do not have delocalised elctrons and electrons are held tight to the atom.
Examples -
Plastic, wood and glass
What are Semi-Conductors, give some examples. [2]
Poor conductor when it is cold, however when it is hot it allows electric current to fo through
silicon, Germanium
When rubbing a perspex rod onto a cloth, what is the charge of the fabric and the rod; and in which direction do the electrons move? [3]
Move of charge : Rod to cloth
Charge of cloth : -
Charge of rod : +
When rubbing a Polythene rod onto a cloth, what is the charge of the cloth and the rod; and in which direction do the electrons move? [3]
Move of charge : cloth to Rod
Charge of cloth : +
Charge of rod : -
State what is meant by the direction of an electric field. [1]
The direction of the force on a positive charge.
What is an Electrical Field? [1]
A region around a charged particle or object within which a force would be exerted on other charged particles or objects.
Describe how to plot an electrical field with a compass and a magnet.[4]
- Place the compass at the end of the magnet
- Mark where the arrow points
- Move the magnet to this point
- Mark where the arrow points again
- Continue doing this until the path leaves the paper or reaches the other end of the magnet
- Repeat(for another starting point at the end of the magnet)
- Show the direction
What direction do electrons travel? [1]
Positive to Negative : + –> -
Describe the relationship between resistance length and area.[3]
Resistance(R)∝Length(L)
Resistance(R)∝1/Area(a)
Resistance(R)∝Length(L)/Area(A)
What is the equation that relates resistivity, resistance, length and area?[1]
p=(R*a)/L
Formula of Resistance [3]
VIR triangle
V(voltage) = I(Current) X R(Resistance)
I(Current) =V(voltage) / R(Resistance)
R(Resistance) = V(voltage) / I(Current)
When a circle’s diameter multiplies, how many times is the area multiplied by in each case?
Area : 2^2 | Diameter : 2X
Area : 9^2 | Diameter : 3X
Area : 8
Area : 243
When a diameter of a circular wire is in each case, how many times is the area multiplied by?
Diameter : 9 | Multiplication Rate : 3
Diameter : 6 | Multiplication Rate : 8
Radius : 6 | Multiplication Rate : 18
Ans : 729x
Ans : 1679616x
Ans : 387420489
How do you measure resistance?
Using both an Ammeter and Voltmeter and using the formula R = V/I
