Define SI base units .

The SI base units are the set of base units from which every other ( derived ) unit in physics can be obtained.

Define a derived unit .

A derived unit is a unit obtained mathematically from a combination of the SI base units .

Express the joule (J) in SI base units.

Using energy = ½ × mass × velocity² : J = kg × (m s -1 ) 2 = kg m 2 s -2

Express the pascal (Pa) in SI base units.

Using pressure = force ÷ area : Pa = (kg m s -2 ) ÷ m 2 = kg m -1 s -2

Units that are obtained mathematically from the SI base units are called .......... units.

Units that are obtained mathematically from the SI base units are called derived units.

True or False? The newton is an SI base unit.

False. The newton is a derived unit — in SI base units it is kg m s -2 .

What is the resolution of a micrometer screw gauge?

0.01 mm — it is used to measure small widths, thicknesses or diameters, such as the diameter of a wire.

What is the resolution of a typical pair of vernier calipers?

Typically 0.1 mm (some are as fine as 0.02–0.05 mm).

State one advantage of digital instruments over analogue instruments.

Digital instruments have greater accuracy and resolution , and give a specific value that is easier to read.

What is a data logger ?

A data logger is an electronic device that automatically monitors and records measurements (e.g. temperature or voltage) over time using sensors, allowing fast and accurate data collection.

Why is a light gate more accurate than a stopwatch for timing?

It removes the error caused by human reaction time (on average about 0.25 s).

On a cathode-ray oscilloscope (CRO), what do the x-axis and y-axis represent?

The x-axis represents time and the y-axis represents voltage (the y-gain).

When reading an analogue meter, always view it from a position .......... to the scale to avoid parallax error.

When reading an analogue meter, always view it from a position perpendicular to the scale to avoid parallax error.

True or False? A micrometer reading should be recorded as 1.4 mm.

False. Micrometer readings should be given to 2 decimal places , e.g. 1.40 mm , matching the instrument's 0.01 mm resolution.

Why is it useful to memorise the approximate values of common physical quantities?

They allow you to make estimates in calculations when exact data is not given in the question.

Estimate the wavelength range of visible light.

Approximately 400 nm (violet) to 700 nm (red).

When making estimates, the gravitational field strength g is usually taken as .......... m s -2 .

When making estimates, the gravitational field strength g is usually taken as 10 m s -2 .

True or False? An estimate must be based on exact, measured data.

False. Estimates use approximate known values (e.g. mass of an adult ≈ 70 kg) to reach a value of the right order of magnitude .

Define random error .

A random error causes unpredictable fluctuations in readings due to uncontrollable factors; it affects precision and is reduced by repeating measurements and averaging.

Define systematic error .

A systematic error arises from a faulty instrument or flawed method and is repeated consistently each time; it affects accuracy and is reduced by recalibrating or improving the method.

Resolution is the smallest change in the quantity being measured that produces a perceptible change in the instrument's reading.

A zero error is a type of systematic error where an instrument reads a non-zero value when the true value is zero, shifting all readings by a fixed amount.

How are uncertainties combined when quantities are added or subtracted, multiplied or divided, and raised to a power?

Adding or subtracting: add the absolute uncertainties Multiplying or dividing: add the percentage or fractional uncertainties Raising to a power: multiply the percentage uncertainty by the power

The uncertainty in a single reading is taken as .......... the smallest division on the instrument.

The uncertainty in a single reading is taken as half the smallest division on the instrument.

True or False? A set of very precise measurements must also be accurate.

False. Measurements can be precise but not accurate — if every reading has the same systematic error , they cluster together (precise) yet sit far from the true value (inaccurate).

Define independent variable .

An independent variable is the variable that is deliberately changed in an experiment.

Define dependent variable .

A dependent variable is the variable that is measured as the independent variable is changed.

In a results table, which variable goes in the first column and which in the second?

The independent variable goes in the first column and the dependent variable in the second, with any repeats and mean values after.

How should a table column heading separate the quantity from its unit?

With a forward slash ( / ) , e.g. length / m .

The variables that are kept the same throughout an experiment are called the .......... variables.

The variables that are kept the same throughout an experiment are called the control variables.

True or False? Categorical data is best displayed on a line graph.

False. Categorical data (e.g. types of material) should be shown on a bar chart or pie chart ; line graphs are for continuous data.

What is meant by the application of science ?

The application of science is the use of scientific knowledge to carry out an investigation , such as developing a new type of radiotherapy.

What four types of implication can a scientific development have?

Commercial — concerning money Legal — concerning the law Ethical — concerning moral principles Social — concerning members of society

How can the reproducibility of an experiment be evaluated?

By repeating it using the given method and checking whether similar results are obtained — the basis of peer review .

A consequence of scientific knowledge, such as its cost or its effect on the environment, is called an .......... of science.

A consequence of scientific knowledge, such as its cost or its effect on the environment, is called an implication of science.

True or False? All applications of science have benefits but no risks.

False. Every application of science has both benefits and risks — e.g. radiotherapy can save lives but also carries the risk of harm from radiation.

Peer review is the process where other scientists in the same field examine published work — checking its data, method and conclusions — helping to validate scientific knowledge.

What is a scientific hypothesis ?

A hypothesis is a testable statement, based on a theory, that predicts what will happen when it is tested.

Why must experimental evidence be published in scientific journals?

So it can be peer-reviewed by other scientists, who check it is a fair test with reasonable conclusions and of a good standard.

Put the four stages of the scientific process in order.

Ask a question about how or why something happens Form a theory (a possible explanation) Make a prediction or hypothesis Carry out an experiment to test it

For a theory to be scientific, it must be able to be .......... .

For a theory to be scientific, it must be able to be tested .

True or False? Once a scientific theory is accepted, it can never be changed.

False. Scientific theories are never indisputable — they are adapted when new, conflicting evidence is found.

Name three types of factor, other than the science itself, that influence decisions made from scientific evidence.

Economic — the cost of implementing changes Social — the effect on people's daily lives Environmental — the effect on plants, animals and surroundings

Why might a government have to justify spending on expensive research, such as a new telescope?

Because the taxpayer money could instead fund areas such as schools or healthcare , so the long-term benefits must be weighed against the cost.

Using wind farms as an example, give an environmental drawback of a technology that is otherwise environmentally friendly.

Although wind is a sustainable energy source, the turbines can harm birds and bats , so their location must take wildlife into account.

Society uses scientific .......... to make decisions about how people live, eat and work.

Society uses scientific evidence to make decisions about how people live, eat and work.

True or False? The people who make decisions based on science are usually scientists themselves.

False. Decisions are mostly made by policy makers, politicians and government , who trust the research rather than being scientists themselves.

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Working as a Physicist (Edexcel A Level Physics): Flashcards

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FrontSI Units
Define SI base units.

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Cards in this collection (51)

Define SI base units.
The SI base units are the set of base units from which every other (derived) unit in physics can be obtained.
Define a derived unit.
A derived unit is a unit obtained mathematically from a combination of the SI base units.
Express the joule (J) in SI base units.
Using energy = ½ × mass × velocity²:
J = kg × (m s^-1)² = kg m² s^-2
Express the pascal (Pa) in SI base units.
Using pressure = force ÷ area:
Pa = (kg m s^-2) ÷ m² = kg m^-1 s^-2
Units that are obtained mathematically from the SI base units are called .......... units.
Units that are obtained mathematically from the SI base units are called derived units.
True or False?
The newton is an SI base unit.
False.
The newton is a derived unit — in SI base units it is kg m s^-2.
What is the resolution of a micrometer screw gauge?
0.01 mm — it is used to measure small widths, thicknesses or diameters, such as the diameter of a wire.
What is the resolution of a typical pair of vernier calipers?
Typically 0.1 mm (some are as fine as 0.02–0.05 mm).
State one advantage of digital instruments over analogue instruments.
Digital instruments have greater accuracy and resolution, and give a specific value that is easier to read.
What is a data logger?
A data logger is an electronic device that automatically monitors and records measurements (e.g. temperature or voltage) over time using sensors, allowing fast and accurate data collection.
Why is a light gate more accurate than a stopwatch for timing?
It removes the error caused by human reaction time (on average about 0.25 s).
On a cathode-ray oscilloscope (CRO), what do the x-axis and y-axis represent?
The x-axis represents time and the y-axis represents voltage (the y-gain).
When reading an analogue meter, always view it from a position .......... to the scale to avoid parallax error.
When reading an analogue meter, always view it from a position perpendicular to the scale to avoid parallax error.
True or False?
A micrometer reading should be recorded as 1.4 mm.
False.
Micrometer readings should be given to 2 decimal places, e.g. 1.40 mm, matching the instrument's 0.01 mm resolution.
Why is it useful to memorise the approximate values of common physical quantities?
They allow you to make estimates in calculations when exact data is not given in the question.
Estimate the mass of an adult human.
Approximately 70 kg.
Estimate the mass of a typical car.
Approximately 1500 kg.
Estimate the wavelength range of visible light.
Approximately 400 nm (violet) to 700 nm (red).
When making estimates, the gravitational field strength g is usually taken as .......... m s^-2.
When making estimates, the gravitational field strength g is usually taken as 10 m s^-2.
True or False?
An estimate must be based on exact, measured data.
False.
Estimates use approximate known values (e.g. mass of an adult ≈ 70 kg) to reach a value of the right order of magnitude.
Define random error.
A random error causes unpredictable fluctuations in readings due to uncontrollable factors; it affects precision and is reduced by repeating measurements and averaging.
Define systematic error.
A systematic error arises from a faulty instrument or flawed method and is repeated consistently each time; it affects accuracy and is reduced by recalibrating or improving the method.
Define resolution.
Resolution is the smallest change in the quantity being measured that produces a perceptible change in the instrument's reading.
Define zero error.
A zero error is a type of systematic error where an instrument reads a non-zero value when the true value is zero, shifting all readings by a fixed amount.
How is the percentage uncertainty of a measurement calculated?
$percentage uncertainty = \frac{uncertainty}{measured value} \times 100 %$
How are uncertainties combined when quantities are added or subtracted, multiplied or divided, and raised to a power?
- Adding or subtracting: add the absolute uncertainties
- Multiplying or dividing: add the percentage or fractional uncertainties
- Raising to a power: multiply the percentage uncertainty by the power
The uncertainty in a single reading is taken as .......... the smallest division on the instrument.
The uncertainty in a single reading is taken as half the smallest division on the instrument.
True or False?
A set of very precise measurements must also be accurate.
False.
Measurements can be precise but not accurate — if every reading has the same systematic error, they cluster together (precise) yet sit far from the true value (inaccurate).
Define independent variable.
An independent variable is the variable that is deliberately changed in an experiment.
Define dependent variable.
A dependent variable is the variable that is measured as the independent variable is changed.
In a results table, which variable goes in the first column and which in the second?
The independent variable goes in the first column and the dependent variable in the second, with any repeats and mean values after.
How should a table column heading separate the quantity from its unit?
With a forward slash ( / ), e.g. length / m.
What type of graph is used to display continuous data?
A line or scatter graph.
The variables that are kept the same throughout an experiment are called the .......... variables.
The variables that are kept the same throughout an experiment are called the control variables.
True or False?
Categorical data is best displayed on a line graph.
False.
Categorical data (e.g. types of material) should be shown on a bar chart or pie chart; line graphs are for continuous data.
What is meant by the application of science?
The application of science is the use of scientific knowledge to carry out an investigation, such as developing a new type of radiotherapy.
What four types of implication can a scientific development have?
- Commercial — concerning money
- Legal — concerning the law
- Ethical — concerning moral principles
- Social — concerning members of society
How can the reproducibility of an experiment be evaluated?
By repeating it using the given method and checking whether similar results are obtained — the basis of peer review.
A consequence of scientific knowledge, such as its cost or its effect on the environment, is called an .......... of science.
A consequence of scientific knowledge, such as its cost or its effect on the environment, is called an implication of science.
True or False?
All applications of science have benefits but no risks.
False.
Every application of science has both benefits and risks — e.g. radiotherapy can save lives but also carries the risk of harm from radiation.
Define peer review.
Peer review is the process where other scientists in the same field examine published work — checking its data, method and conclusions — helping to validate scientific knowledge.
What is a scientific hypothesis?
A hypothesis is a testable statement, based on a theory, that predicts what will happen when it is tested.
Why must experimental evidence be published in scientific journals?
So it can be peer-reviewed by other scientists, who check it is a fair test with reasonable conclusions and of a good standard.
Put the four stages of the scientific process in order.
- Ask a question about how or why something happens
- Form a theory (a possible explanation)
- Make a prediction or hypothesis
- Carry out an experiment to test it
For a theory to be scientific, it must be able to be ...........
For a theory to be scientific, it must be able to be tested.
True or False?
Once a scientific theory is accepted, it can never be changed.
False.
Scientific theories are never indisputable — they are adapted when new, conflicting evidence is found.
Name three types of factor, other than the science itself, that influence decisions made from scientific evidence.
- Economic — the cost of implementing changes
- Social — the effect on people's daily lives
- Environmental — the effect on plants, animals and surroundings
Why might a government have to justify spending on expensive research, such as a new telescope?
Because the taxpayer money could instead fund areas such as schools or healthcare, so the long-term benefits must be weighed against the cost.
Using wind farms as an example, give an environmental drawback of a technology that is otherwise environmentally friendly.
Although wind is a sustainable energy source, the turbines can harm birds and bats, so their location must take wildlife into account.
Society uses scientific .......... to make decisions about how people live, eat and work.
Society uses scientific evidence to make decisions about how people live, eat and work.
True or False?
The people who make decisions based on science are usually scientists themselves.
False.
Decisions are mostly made by policy makers, politicians and government, who trust the research rather than being scientists themselves.

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