A student uses a balance and a measuring cylinder of water to find the density of a cork.
The value the student calculates is much larger than the true density of cork.
Which of these explains the error?
Air bubbles were trapped on the cork when it was under the water
The balance was not zeroed and read 0.5 g0.5\ \text{g}0.5 g below the true value
The cork was dried with a paper towel before it was put on the balance
The cork floated, so only part of it was below the water surface
44 exam-style questions on OCR GCSE Physics 1.1 The particle model, covering 1.1.1 Development of the atomic model, 1.1.2 Structure of the atom, 1.1.3 The size of atoms and small molecules, 1.1.4 Density, 1.1.5 Density and the states of matter, and 1.1.6 Density, mass and volume. Each one has a worked solution and a mark scheme showing where the marks go.