Ms Flashcards
Investigate shape and direction of magnetic field
Use a compass to show shape by placing compass around magnet
Move compass in new position and mark direction again
Link directions together to find field line pattern
Use a plotting compass to show direction, points to South Pole
Why does a car have greater acceleration without the caravan on it
Mass and acceleration are inversely proportional f=ma
Total mass is less so less air resistance and friction
Less work/ energy used in relation to amount of fuel
Half life definition
Time for half of radioactive atoms to decay and radioactivity to half
Products of fission
Daughter nuclei
Three neutrons
Gamma radiation
Purpose of the moderator (2)
Slows down/ reduces energy of neutrons to increase rate of fission
Increases absorption of neutrons by nuclei
What happens if control rod is removed (3)
Rate of reaction increases
Fewer neutrons are absorbed out of the reactor by control rod so more neutrons collide with uranium
Temperature increases
Problems on surrounding area due to a nuclear accident (7)
Harmful to nature/ danger to life
High activity levels
Long half life’s difficult for workers to access area/ need protective clothing
Special handling equipment
Distance from hazard zone
Radioactive material mixes with local environment such as soil water air
Distant already due to wind or water
Reasons why water flow stops in that thing
Flow when pressure difference, ends when pressure is equal
Pressure causes force on water (P=f/a)
Pressure acts in all directions
How to find age of rock using radioactivity (5)
There is a known reactivity when rocks are formed
Measure the proportion of uranium of activity now
Compare activity now to original activity
Determine the number of half lives elapsed
Calculate age from reference of half life
How are earth wires a safety feature (5)
Earth wire is connected to casing If casing becomes live/ live wire touches casing Provides a low resistance path Large surge of current in earth wire Fuse breaks causing current to stop
How do electric motors spin (5)
Current in coil causes magnetic field around wires of coil
This field cuts permanent magnet field
Force on the wire
Flemings left and rule
Force up on one side force down on the other
Why is shielding in a nuclear reactor necessary (3)
Waste is radioactive
Radiation ionises cells
Radiation is very penetrating
Explain an increase in resistance (3)
Lamp heats up
Greater chance of electron collisions
Resistance increases
Difference between transverse and longitudinal waves
Longitudinal vibrations are parallel to the direction of transfer
Transverse vibrations are perpendicular to direction of transfer
How are fuses protecting
Fuse is in the live wire
When current gets too high due to a fault
Fuse breaks the circuit by melting
Why is it not good for a too low fuse
Unable to use appliance as it won’t work since current is too low
Reasons for anomalies for car down a ramp experiment
Pushed at different strengths
Different reaction times
More the car moves the more friction
Measuring background radiation
Geiger muller detector
Remove radioactive substance
Repeat for different times of the day
Why would less 🐟 particles reach the detector during a fire (2)
🐟 are absorbed/ deflected/ scattered
🐟 affected/ blocked by smoke
How is there pressure inside a tyre
Continuous random movement of molecules collide with the walls of the tyre
A force is produced by the bombarding of molecules so a pressure/ force is exerted on an area
How do you find accurate results for finding resistance
Use a thermometer and a water bath/ allow wires to cool
V=IR
Repeat and average
Interpolated/ additional points
Linear part of graph and use gradient
How to accurately find the refractive index of glass
Use a ray box and vary i to obtain a range of values
N= sinI/sinR
Plot graph for sinI and sinR, calculate gradient
Use a sharp pencil and a ruler
Reasons for data logger showing varying voltage of a magnet through a coil
Voltage is induced
Field lines are cut
Current changes when magnet does
Magnets slows down so amplitude decreases
Black and white hard drives losing more heat wen black on top
Transfer heat by conduction as they emit IR radiation so emit thermal energy
Black emits and loses more heat than white
Thermal energy flows at equilibrium temperature
Explain how radioactivity decreases over time
Activity is due to nucleus decaying overtime so less radioactive nuclei are left
Number of nuclei decaying per second decreases
What is meant by the term total internal reflection
Reflection occurs inside the optically more dense medium
All the light is reflected
Incident angle is greater than critical angle
What do variable resistors control
Circuit resistance and current
