2.1 Physical quantities and units, 2.2 Making measurements and analysing data & 2.3 Nature of quantities

What is the percentage difference?

How close the experimental value achieved from an experiment is to the accepted value

Percentage difference = (measured value - accepted value) / accepted value x 100

What is a random error?

An error that causes the readings to be spread about the true value, due to results varying in an unpredictable way

How can the effect of random errors be reduced?

By making more measurements and calculating the mean

What is a systematic error?

An error that causes readings to be different from the true value by a predictable amount

What is a zero error?

When an instrument does not read zero when it should

What is a parallax error?

The error that occurs when the line of sight of the person making a measurement is not perpendicular to the scale

What affect do random errors have on a graph?

A scatter of points are about the thine of best fit

What affect do systematic errors have on a graph?

The line of best fit is moved away from where it should be

What is a precise measurement?

A measurement where there is very little spread about the mean value

What is a accurate measurement?

A measurement that is close to the true value

What are repeatable measurements?

Measurements where the same results are obtained if the original experimenter repeats the experiment w/ the same equipment

What are reproducible measurements?

Measurements where similar results are obtained if a different experimenter repeats the experiment w/ different equipment

What is the resolution of a measuring instrument?

The smallest change in the quantity being measured that the instrument can detect

Is displacement a vector or scalar quantity?

Vector

Is velocity a vector or scalar quantity?

Vector

Is acceleration a vector or scalar quantity?

Vector

Is force a vector or scalar quantity?

Vector

Is momentum a vector or scalar quantity?

Vector

Is torque a vector or scalar quantity?

Vector

Is moment due to a force a vector or scalar quantity?

Vector

Is distance a vector or scalar quantity?

Scalar

Is speed a vector or scalar quantity?

Scalar

Is mass a vector or scalar quantity?

Scalar

Is temperature a vector or scalar quantity?

Scalar

Is time a vector or scalar quantity?

Scalar

Is pressure a vector or scalar quantity?

Scalar

Is energy a vector or scalar quantity?

Scalar

Is work done a vector or scalar quantity?

Scalar

Is power a vector or scalar quantity?

Scalar

What is a scale vector diagram?

A diagram with the vectors drawn to the correct length according to the given scale and the angles have been drawn the correct size using a protractor

What is the vertical component of the vector F with the angle θ to the horizontal?

Fsinθ

What is the horizontal component of the vector F with the angle θ to the horizontal?

Fcosθ

Why is momentum a vector?

Momentum is the product of mass and velocity, and velocity is a vector

Why does the mass of a box on a slope not affect the angle at which it begins to slip?

As the mass increases, the weight increases, but so does the frictional force ∴ the mass cancels and does not affect the angle

What is the resolution of vernier calipers?

0.1mm

What is the resolution of a ruler?

1mm

What is the resolution of microeters?

0.01mm

What does a direct current look like on an oscilloscope?

Straight line

What does an alternating current look like on an oscilloscope?

Sinusoidal waveform

What does a galvanometer detect?

It detects and measures small electric currents

It is often used in null methods, where an unknown value is measured by adjusting the circuit until the reading on the galvanometer is zero, giving very accurate measurements

What is a potential divider?

A circuit with several resistors in series connected across a voltage source, to produce a required fraction of the source potential difference

What is a hall probe?

Used to measure magnetic field strength, and must be used perpendicular to the field being investigated to prevent it from only measuring a component of magnetic strength