WAAP PPQs Flashcards
A ball bearing in an experimental set-up has a diameter of about 1cm. Describe how the diameter could be measured accruately [2]
Use a micrometer
Measure diameter in different places and calculate mean
A student carries out measurements to determine the density of glass. The student has 20 glass microscope slides available.
P=m/v
Describe how the student can determine an accurate value for the density of glass [4]
- student should use a weighing scale to weigh the mass of all 20 glass microscope slides
- use a micrometer to measure sides
- use vernier capiler to measure (longer) side
- repeat and determine mean for at least one measurement.
State one precaution that the student should take when measuring small measurements to ensure they are accurate.
Check zero error on micrometer
Describe what physicists mean by error and uncertainty [2]
- error is the difference between the result and the true value
- uncertainty is the interval in which the true value can be considered to be
Give two reasons why a measurement may have an uncertainty
- the instrument being used to make the measurement
- the way in which the measurement is made
- quantity measured not being constant
Discuss the advantages of using a graph [3]
- allows trend to be identified
- anomalies can be identified
- systematic errors can be detected
- line of best fit ‘averages’ results
- allows interpolation
- allows gradient to be determined
Which of the following best describes newton as used in physical measurements
Base quantity
Base unit
Derived quantity
Derived unit
Derived unit
A conductor has a resistance R. A constant potential difference is applied across the conductor. The drift velocity of the charge carriers in the conductor is v.
What is the relationship between R and v?
v (fish symbol) 1/R
Which of the following units is equivalent to the SI unit for energy
Kgms^-2
kWh
Nm^-1
Ws
Ws
