Phys paper 1

• Kinetic energy equation


  KE = 1/2 x m x v^2
• Charge flow equation


  current x time (s)
• Potential difference equation


  current x resistance
• power equation with potential difference

  current x potential difference
• energy transferred equation with p.d and charge

  charge flow x potential difference
• Weight equation


  weight= mass x gravitational strength
• SHC RQ


  1. measure and record mass of copper block in kg.

  2. place a heater in the larger hole in the beaker

  3. connect the ammeter,powerpack and heater in series

  4. connect the voltmeter across the power pack

  5. use the pipette to put a small amount of water in the other hole. put the thermometer in this hole

  6. switch the powerpack to 12V. switch it on

  7. record the current readings using ammeter and pd readings using voltmeter. they shouldnt change

  8. measure the temp and switch on the stop watch

  9. record temp every 10 mins, 10 times

  10. add results to table

  11. calculate temp change, mass and change in thermal energy (V x I= W) then (W x s= J)
• thermistor


  Resistor which varies with temperature

  
  

  -Used in electrical thermometers
• Variable resistor


  A resistor whose value can be varied between its minimum and maximum values.
• Why devices waste energy and how to reduce the problem

  -friction moving between mving parts causes heating➡️ lubricate the moving parts to reduce friction

  
  

  -sound created by machines causes energy to be dissipated ➡️ cut out noise,e.g. tighten loose parts to reduce vibration
• how to determine density of a rock

  -measure rock using a scale

  - part fill a measuring cylinder with water and measure the first volume

  -fill eureka can with water leve upto the spout

  -place rock in water and collect displaced water& measure with measuring cylinder

  -volume of rock =volume of water

  -work out density= mass/volume
• how is risk from internal contamination different to risk from external contamination?

  -low penetrating ability

  -stopped by skin

  -internally, highly ionising:absorbed by organs

  -contamination will cause harm to cells
• negative of fossil fuels

  releases co2 , causes global warming
• parallel circuit


  An electric circuit with multiple paths
• Current-potential difference graph for

  a filament bulb

  As temperature increases, resistance increases

  
• thermal conductivity RP


  1. Place a small beaker into a larger beaker.

  2. Fill the small beaker with hot water from a kettle.

  3. Put a piece of cardboard over the beakers as a lid. The lid should have a hole suitable for a thermometer.

  4. Place a thermometer into the smaller beaker through the hole.

  5. Record the temperature of the water in the small beaker and start the stopwatch.

  6. Record the temperature of the water every 2 minutes for 20 minutes.

  7. Repeat steps 1-6, each time packing the space between the large beaker and small beaker with the chosen insulating material.

  8. Plot a graph of temperature (y-axis) against time (x-axis).
• thermal conductivity in a building

  -Rate of cooling is low and thermal conductivity is high: if walls are thick

  -heat would be lost very quickly if walls are thin
• result of high temp for gas particles

  higher temp

  ➡️moves faster

  ➡️more kinetic energy

  ➡️hit walls harder and more often

  ➡️pressure increaes as force is greater

  ➡️container may burst
• gas pressure


  the force exerted by a gas per unit surface area of an object
• solids description


  -fixed shaped as particles are tightly packed

  -very dense

  -particles have no space to move (forces become repulsive)

  -vibrate about fixed point

  -strong forces of attraction
• Gases description


  -particles far apart

  -space between particles (easy to compress)

  -move randomly

  -negligible, no forces of attraction

  -spread out in different directions
• latent heat of fusion

  amount of energy needed to change a unit mass of a substance from solid to liquid
• alpha decay


  atomic number decreases by 2

  mass number decreases by 4
• radioactive contamination


  the unwanted radioactive isotopes end up on other materials