Physics (feb mocks) Flashcards
In a series circuit, what happens to the voltage?
Voltage is shared, total voltage is all voltages added together
In a series circuit, what happens to the current?
Current is the same throughout the circuit
In a parallel circuit, what happens to the voltage?
Voltage is the same throughout the circuit
In a parallel circuit, what happens to the current?
Current is shared, total current is all currents added together
Are ammeters connected in series or parallel? What do they measure?
Series, current
Are voltmeters connected in series or parallel?
Parallel, voltage
What is resistance? What is it measured in?
The opposition to current flow, ohms
What does ohms law state?
There is a directly proportional relationship between current and potential difference, provided the temperature stays the same
How do you calculate voltage?
Voltage = current x resistance
How do you calculate resistance?
Resistance = voltage/current
How do you calculate current?
Current = voltage/resistance
In series, what happens when adding multiple resistors?
resistance increases and current decreases as more are added?
In parallel, what happens when adding multiple resistors?
Resistance decreases and current increases as number of resistors increases
How can energy be transferred in a circuit?
mechanically (by a force), electrically, by heating or by radiation
What are 5 energy stores?
Chemical (food, fuel), GP (objects in high positions), EP (stretched, squashed or twisted objects, thermal (in hot objects) kinetic (moving objects)
What is dissipation?
Energy transferred to the environment by heat, sound or light
What is direct current?
Electrical charged pushed in ONE DIRECTION around a circuit
What is alternating current?
where the direction of current keeps changing
Which, A.C or D.C, supplies mains electricity
AC
How to calculate power (voltage)?
Power = current x voltage
What is power measured in?
Watts (W)
What is energy transferred measured in?
Joules (J)
How to calculate power (resistance)?
Power = current^2 x resistance
How to calculate power?
Energy transferred/time
How to calculate Kinetic energy?
KE = 1/2 x mass x velocity^2
How to calculate GPE?
GPE = mass x gfs x height
How to calculate weight?
Mass x gfs
What is the unit for weight?
Newtons
Which is a force: mass or weight?
Weight
Does mass change at different places in the universe?
No, it is the same everywhere
What is gravity and what factors affect it?
The force of attraction between two objects, mass and distance
What are the units for GPE and KE?
Joules
What is work done?
How much energy occurs when a force is used to move an object by a distance
How do you calculate work done?
work done = force x distance
How do you calculate power (work done)?
Power = work done/time
Where is the magnetic field strongest?
Closer to the magnet’s poles
What direction do magnetic fields always point?
North to South
What is the motor effect?
A current carrying wire in presence of a magnetic field will experience a force, wire has to be perpendicular
How do you measure force (magnetic flux)?
Force = magnetic field strength x current x length
What is magnetic flux density?
Magnetic field strength
What is the magnetic field like inside a solenoid?
Strong and uniform
What is the magnetic field like outside a solenoid?
Weak (cancel out)
How do you increase the magnetic field strength?
Increase current, turn coil more times, use a shorter wire with the same amount of turns, add a soft iron core
What is a fuse? Benefits and drawbacks?
A thin wire which melts to break the circuit when the current gets to high. Simple and cheap but has to be replaced
What is newtons first law?
A resultant force is required to change the motion of an object, if resultant force is zero then a stationary object will remain stationary and a moving object will continue moving at the same velocity
What is inertia?
Where there is no change on the movement of an object
What is Newtons second law?
if a non-zero resultant force acts on an object, then it will cause it to accelerate. The size of a resultant force is directly proportional to the acceleration is causes
How to measure force?
Force = mass x acceleration
What is resultant force?
The overall force when two or more forces are acting on an object (in a direction)
What is Newtons third law?
When 2 objects interact, the forces they exert are equal and opposite to each other. Equal in magnitude and opposite in direction.
What does friction do?
Slows down moving objects
What is upthrust?
Upwards fore in a fluid
What is magnetic flux density measured in/?
Teslas
Left hand rule
thumb - force
index - field
middle - current
