Physics 0625 · IGCSE · Physical quantities and measurement techniques

Physical quantities and measurement techniques — practice question

A student finds the volume of a block of modelling clay using two different methods.
(a(i))[2]

Measure the length l, width w and height h of the modelling-clay block in Fig. 1.1. Give your answers in centimetres, rounded to the nearest millimetre.

(a(ii))[1]

Calculate a value $V_A$ for the block’s volume. Use your measurements from (a)(i) together with the equation: $V_A=l\times w\times h$.

(b)[2]

Suggest why $V_A$ is only an approximate value for the block’s volume. Describe how the accuracy of $V_A$ may be improved.

(c)[1]

Another student measures the dimensions of a block of clay that is much smaller than the block in (a). Suggest why these measurements may be less accurate than yours, even if they are carried out carefully.

(d(i))[1]

State the volume $V_1$ of the water in the measuring cylinder shown in Fig. 1.2.

(d(ii))[1]

Describe briefly how a measuring cylinder is read so that an accurate value for the volume of water is obtained.

(e)[1]

State the new reading $V_2$ from the measuring-cylinder scale in Fig. 1.3. Calculate another value $V_B$ for the volume of the block. Use your measurements from (d)(i) and (e) together with the equation $V_B=(V_2-V_1)$.

(f)[2]

Suggest one possible source of inaccuracy in Method 2 and suggest one improvement to lessen its effect.

Worked solution & mark scheme

This 11-mark question has a full step-by-step worked solution and mark scheme. One marking point: l is 6.9 cm

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