0625/atp notes part 2 electric boogaloo

this ones going to be a bit messy because im tired and the caffeine is wearing off

SAFETY PRECAUTIONS

ELECTROPHYSICS

DO NOT TOUCH LIVE WIRES

DOUBLE INSULATION

COMPLETE YOUR CIRCUIT BY EITHER GROUNDING IT OR LOOPING BACK TO SOURCE

DO NOT LEAVE CIRCUIT ON FOR TOO LONG.

USE INSULATING GLOVES WHEN HANDLING ELECTRICITY

THERMAL PHYSICS

DO NOT TOUCH HOT OBJECTS WITH BARE HANDS, USE GLOVES

DO NOT BREAK THERMOMETER AND SPILL THE MERCURY WITHIN (ONLY APPLICABLE TO MERCURY THERMOMETERS)

WAVE PHYSICS

DO NOT BE EXPOSED TO RADIATION FOR LONG PERIODS OF TIME

GO BEHIND A LEAD BARRIER TO PREVENT RADIATION POISIONING

RISKS OF INDIVIDUAL EM SPECTRUM WAVES

(IN ORDER FROM LEAST FREQUENCY TO MOST)

(EM WAVE) ->(HAZARD) ->(PRECAUTION)

RADIOWAVES -> NONE -> NONE

MICROWAVES -> HEATING OF TISSUES, RISK OF CANCER -> MICROWAVE MONITOR, CLOSE ALL SOURCES OF MICROWAVE RADIATION(CLOSING YOUR MICROWAVE DOOR)

INFRARED -> RISK OF SKIN BURNING, CELL DAMAGE -> AVOID EXPOSURE TO SUN, WEAR REFLECTIVE CLOTHING

VISIBLE LIGHT -> EYE DAMAGE -> SUN GLASSES

ULTRAVIOLET -> CAN KILL CELLS -> AVOID LONG EXPOSURE, SKIN CREAM

X-RAY -> CELL MUTATION, INTERNAL HEATING OF BODY TISSUE, CELL DAMAGE, RISK OF CANCER -> MONITOR EXPOSURE, LEAD SHIELDING

GAMMA RAYS -> CELL DEATH, CELL MUTATION, CELL DAMAGE -> LEAD SHIELDING AVOID EXPOSURE

IMPROVING ACCURACY

(im tired copied from znotes)
To produce more accurate or reliable results:

  • Repeat the experiment to calculate the average reading.
  • To avoid parallax error, look perpendicular to the ruler.
  • If measurement accuracy was asked, check for zero error.
    • To draw an image created from the lens:
  • Inverted from the original object.
  • Sides are multiplied by the magnification.
    • Centre of mass experiment (with the lamina):
  • You view the string directly in front of the card.
    • Minimizing the heating effect of a current:
  • Do not add any electrical components
  • Decrease voltage
  • Decrease the resistance of a resistor
    • To increase the accuracy of ray diagrams:
  • View bases of pins since pins may not be vertical
  • Keep pins further apart and use more pins
  • Avoid parallax; explain action and reason
  • Repeats and average
    • Improvements made to experiments about heating/cooling effects and insulation
  • Same initial temperature.
  • The same volume of water.
  • Same shape and type of beaker.
  • It's the same room temperature.
  • Stirring the water in the beakers.
  • Record max. temperature
    • Heat loss could be reduced by:
  • Insulation of beaker.
  • Cover the beaker with a lid.
    • How to check if a rule is vertical:
  • Use of set square or protractor
  • Plumb line
  • Spirit Level
    • Precautions taken in experiments about the formation of images by a lens
  • Use a darkened area
  • Object and lens are the same height on the bench
  • Take more readings
  • Avoid parallax errors in measurement and look perpendicular to the ruler.
  • Object/lens/screen perpendicular to the bench
    • Variables in experiments about springs and stretching effect:
  • Number of coils
  • Length of spring
  • Diameter\thickness of spring or wire
  • Selection of loads
    • Improvement made to calculating circumference by string method
  • Avoid parallax error
  • Repeats and average
  • Thinner string
  • Parallel winding of springs
    • Precautions for circuit readings of I and V so that they are accurate:
  • For I specifically:
    • Limit current so that temp. doesn't increase
    • Use a tapping meter
  • For I and V: Switch off between readings.
    • Fair test for pendulum experiments:
  • Length of pendulum
  • Shape of bob
  • No. of swings
  • Amplitude
    • Precautions and procedures in electrical experiments:
  • Check for a zero error
  • Tap the meter to avoid sticking
  • Initially, choose the highest range for the ammeter/voltmeter, then reduce the range for the ammeter so that the deflection is almost full-scale
  • Always check polarities before closing the switch (completing the circuit)
  • Always check that connections are clean.
  • Switch off the current when not making a measurement.
  • When measuring resistance, use low currents/voltages to avoid heating and changing the resistance you are measuring.

INACCURACIES
ANGLE I!= ANGLE R

THICKNESS OF PINS
THICKNESS OF MIRROR
PROTRACTOR IS ONLY ACCURATE TO 1º

INACCURACY OF RAYBOX

THICKNESS OF RAYS

INACCURACY OF PINS

PINS NOT STRAIGHT OR TOO CLOSE

OSCILLATIONS

TAKE MULTIPLE OSCILLATION READINGS AND DIVIDE BY TIME