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ICSE Class 7 Physics Question 9 of 18

Physical Quantities and Measurement — Question 12

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Question

Question 12

The mass of a lead piece is 115 g. When it is immersed into a measuring cylinder, the water level rises from 20 mL mark to 30 mL mark. Find:

(i) the volume of the lead piece,

(ii) the density of the lead in kg m-3.

Answer

(i) Mass = 115 g;
Initial volume V1 = 20 mL;
Final volume V2 = 30 mL;
Volume of lead piece = V2 - V1 = 30 - 20 = 10 mL

1 mL = 1 cm3
10 mL = 10 cm3

So, volume of the lead piece = 10 cm3.

(ii) Density = ? Density=MassVolumeDensity=11510=11.5g cm3\text{Density} = \dfrac{\text{Mass}}{\text{Volume}} \\[1em] \text{Density} = \dfrac{\text{115}}{\text{10}} = 11.5 \text{g cm}^{3}

1 g cm-3 = 1000 kg m-3
11.5 g cm-3 = 1000 x 11.5 = 11500 kg m-3

So, density of lead = 11500 kg m-3.