September Exams Flashcards
How’s an image made
Refracting light
Real vs virtual
Real - light rays come together / virtual - they don’t
Inertial mass
How hard it is to change the velocity of an object
Inertia
Objects stay still / same speed if no resultant force is applied
Newton’s 2nd law
Acceleration of an object is proportional to the resultant force acting on the object. It’s inversely proportional to the mass if the mass is greater the acceleration is smaller
Acceleration in fluid
The object is object falling in a fluid initially accelerate due to gravity, eventually resultant force = 0 and objects balanced meaning it travels at its terminal velocity (constant speed)
Acceleration meaning
How fast something speeds up/slows down, rate of velocity change
What’s the atmosphere
Thin layer of air around the Earth, gets less dense with increasing altitude
What happens to ur pressure if ur higher up in the atmosphere and why?
the density of gas particles is higher CLOSER to the Earth so more collisions between particles in an object so pressure is higher.
The higher up you are the less gas particles, weight, is above you so LESS pressure HIGHER UP
What happens if forces cancel eachother out
They are balanced so object is moving at a constant speed or stationary
Scalar vs vector quantities + examples
Scalar = magnitude (size) - speed Vector = magnitude and direction - force
Magnitude meaning
Size
Alternating vs direct current
Alternating-current continuously changed its direction, going back and forth a direct current is always flowing in the same direction
Mains supply Voltage and Hz
Voltage = 230 Hertz = 50
Potential difference meaning
Difference of electrical potential between two points
Current meaning
Rate of flow of electrical charge
Resistance
Measure of opposing current flow in a circuit
What should ammeter be connected in and what does it measure
Series
Measures direct and alternating current in amps
What should voltmeter be connected in and what does it measure
Parallel
Voltage
Live wire in mains electricity + danger
BROWN
Carries alternating potential difference from supply
Can cause electrocution
Neutral wire in mains electricity
BLUE
Completes the circuit
Earth wire in mains electricity
GREEN+YELLOW STRIPES
safety wire to stop appliance becoming live, only carries current if there is fault
Potential difference between live wire + earth
230V
What are the dangers of providing connection between earth and live wire
Electrocution/shock/fires
Power (2 meanings)
Rate at which energy is transferred
Rate at which work is done
