Minimising heating effect of a current:
• Lower current
• Lower voltage
• Add a lamp
• Increase resistance of a resistor
To increase accuracy of ray diagrams
• View bases of pins since pins may not be vertical
• Keep pins further apart
• Use more pins
• Avoid parallax, explain action and reason
• Repeats and average
Adjustments made to experiments will be made to increase accuracy
Improvement made to experiments about heating effect and insulation
• Lids
• Repeats
• Stirring
• Record max. Temperature
• Add insulation
• Keep constant room temperature
• Avoid heat loss
How to check if a rule is vertical:
• Protractor
• Use of set square
• Plumb line
• Spirit Level
Precautions taken in experiments about formation of images by a lens
• Use a darkened area
• Meter ruler on bench or clamped
• Object and lens same height on bench
• Mark on lens holder to show centre of lens
• Take more readings
• Avoid parallax error, explain action and reason
• Lens\screen perpendicular to bench
Variables in experiments about springs and stretching effect:
• Number of coils
• Length of spring
• Diameter\thickness of spring or wire
• Range of loads
• Length of wire
• Coil spring
Periodic time (T) is measured by timing a number (n) of oscillations, then divide (n) by the time taken.
Drawing graphs:
• Label axis
• Choose a proper scale
• Well judged best fit line
• Thin and neat lines
Measuring the gradient:
• Draw a triangle on graph
• Use clear lines
• Triangle must be larger than half the line
Sources of error in calculating circumference by string method:
• Parallax
• Diagonal winding
• Thickness of string
Improvement made to calculating circumference by sting method
• Avoid parallax error
• Repeats and average
• Thinner string
• Parallel winding of springs
hope this helps...
best of luck!!!
