Topic 1,2,3 Flashcards
What is induction
Using charged object to force charges in an uncharged object to move
Current is
The rate of flow of charge around the circuit.
Will only flow through a component if there is a voltage across that component
What is voltage
(Potential difference) is the driving force that pushes the current round
Like “electric pressure”
What is resistance
Anything in the circuit which slows the flow down
Ohms
What happens if u increase resistance
Less current will flow
What happens if you increas the voltage
More current will flow
Potential difference is
The energy transferred per unit charge passed
What happens when an electrical charge goes through a change in potential difference
Energy is transferred
What happens when the charge reaches a component in the circuit
It gives up its energy when it ‘falls’ through any voltage drop
The bigger the voltage of the battery
The energy that will be supplied to the circuit for every coulomb of charge which flows around it
As charge is raised “higher” at the start so more will be displaced
Current is ……..In a circuit (and junction)
Conserved
Ammeter is in a ……
Series
In line with a component
What kind of circuit must a voltmeter be in
Parallel around the component under test
Component, ammeter and variable resister are in a series so can be placed in…….
Whereas voltmeter must me in…..
Any order
Parallel
Resistance of an LDR in bright light and darkness
Bright-resistance falls
Darkness-resistance highest
A thermistor in hot and cold conditions
Hot-resistance drops
Cold-resistance goes up
What happens when there is an electrical current in a resistor
Energy transfer which heats the resistor
Due to electrons colliding with ions in the lattice that make up the resistor as they move through
Giving ions extra energy, emitted by heat, increasing resistors resistance
Problems with electrical current
Heating effect makes electrical circuits less efficient as energy wasted as heat
Cause components to melt, circuit stop working or not properly
How do fuses protect circuits
They melt and break the circuit if the current get too high
Give an example of where the heating effect of resistors if good
Toasters continue coil of wire it’s high resistance
Current passes through and temp increases so glows giving of infrared (heat) radiation which cooks bread
Also lightbulbs
The difference between speed and velocity
Speed is how fast you’re going with no regard for direction
Velocity must also have direction specified. The distance in a particular direction is called DISPLACEMENT
Acceleration is
How quickly the velocity is changing
Can be change in speed or direction or both
Both acceleration and velocity (and displacement) are vector quantities so have
Magnitude and direction
In a distance time graph gradient =
Speed
In a velocity time graph, gradient =
Acceleration
In a velocity time graph the distance travelled equal to
The area under the graph
In stationary objects all forces are
Balanced due to gravity (or weight) acting downwards causing a reaction force from the surface pushing the object back up
Equal horizontal forces to prevent acceleration
In steady horizontal velocity and steady vertical velocity all forces
Must be balanced
Off unbalanced causes excels ration not steady speed
Horizontal and vertical acceleration causes forces to be
Unbalanced
Length of arrow longer showing overall resultant force
Perpendicular direction forces are still balanced
What is weight and what is it caused by
Force measured in newtons (N)
Caused by full of gravity
Will be different anywhere in universe
Mass is not
A force
Is the amount of ‘stuff’ in an object
Same value anywhere in universe
Measured in kilograms
Falling objects in a vacuole accelerate at
The same rate
A vacuum is a place
That doesn’t contain any matter
The accelerating force acting on all objects is
Gravity
Why do two objects fall at the same rate in space(vacuum)
Because there is no air in a vacuum so no air resistance to slow down the falling objects
How does terminal velocity accure
On earth when an object first sets of they have more force accelerating them than resistance slowing them down
As speed increases as does air resistance
Reducing acceleration so that thus forces are equal
When balanced object won’t accelerate any more has reached maximum speed or terminal velocity
What happens if object a exerts a force on object B
Object B exerts the exact opposite force on object A
What is action and reaction forces
Action- you pushing something e.g shopping trolly
Reaction- trolley pushing back against you
What happens if there is zero resulting force acting on a body (forces are balanced)
Body will remain at rest or else if already moving will carry on at the same velocity
When something is moving at a constant velocity then
The forces on it must be balanced
No resultant force
To keep going at a steady speed the must be
Zero resultant force
If the resulting force acting on a body is not zero (not equal)
It will accelerate in the direction of the resultant force (or decelerate)
Name the five different forms of acceleration
Starting Stopping Speeding up Slowing down Changing direction
Name three factors effecting the rate of acceleration
Bigger resultant force, greater acceleration or deceleration
Bigger mass of object, smaller a creation
To get big mass to accelerate as fast as a small mass needs bigger resultant force
