Paper 6
Common Questions & Answers:
Topic 1:
- Reason for measuring 20 oscillations / 5 marbles = Reduce the effect of timing error /
effect of uncertainty reduced.
- Obtaining measurement of a circular object: Place the circular object in between 2
wooden blocks and measure the gap (1). Rotate the object on different axes and calculate
the average measurement (1).
- Technique for ensuring the ruler is as near as possible on being balanced: Measure the
distance of each end of the ruler to the bench.
Topic 2:
- Look at the scale perpendicularly to eye level. (Precaution)
- Look from the bottom of the meniscus. (Precaution)
- Avoid the thermometer from touching the wall. (Precaution)
- Source of error: (usually) measuring cylinder too big, causing graduations’ interval to be
too large.
- Source of error: Test-tube too small - height change insignificant.
- As the temperature of water decreases, the rate of temperature decreasing decreases.
Thus, the initial water temperature must be the same.
Topic 3:
Ray Diagram:
- To obtain a sharp image: Move the screen back and forth very slowly (if the distance
between the screen and image is the dependent variable) / Move the lens back and forth
very slowly (if the distance between lens and object isn’t the independent / control
variable).
Reflection / Refraction:
- Use a sharp pencil. (Precaution)
- Pins should be at least 5 cm apart. (Precaution)
- Keep pins vertical. (Precaution)
- Difficult to obtain the same result: Difficult to align pins accurately.
Common Questions & Answers:
Topic 1:
- Reason for measuring 20 oscillations / 5 marbles = Reduce the effect of timing error /
effect of uncertainty reduced.
- Obtaining measurement of a circular object: Place the circular object in between 2
wooden blocks and measure the gap (1). Rotate the object on different axes and calculate
the average measurement (1).
- Technique for ensuring the ruler is as near as possible on being balanced: Measure the
distance of each end of the ruler to the bench.
Topic 2:
- Look at the scale perpendicularly to eye level. (Precaution)
- Look from the bottom of the meniscus. (Precaution)
- Avoid the thermometer from touching the wall. (Precaution)
- Source of error: (usually) measuring cylinder too big, causing graduations’ interval to be
too large.
- Source of error: Test-tube too small - height change insignificant.
- As the temperature of water decreases, the rate of temperature decreasing decreases.
Thus, the initial water temperature must be the same.
Topic 3:
Ray Diagram:
- To obtain a sharp image: Move the screen back and forth very slowly (if the distance
between the screen and image is the dependent variable) / Move the lens back and forth
very slowly (if the distance between lens and object isn’t the independent / control
variable).
Reflection / Refraction:
- Use a sharp pencil. (Precaution)
- Pins should be at least 5 cm apart. (Precaution)
- Keep pins vertical. (Precaution)
- Difficult to obtain the same result: Difficult to align pins accurately.
