The graph shows the variation with time of the height through which a crane lifts a mass of20 kg.Assume the gravitational field strength g is 10 N / kg, and…

Which of the following atoms / ions contain(s) exactly 18 electrons?1 18O82 34S163 35Cl174 37Cl–175 40Ca2+20 Answer: In an atom, the number of electrons equals the atomic number (the number…

A woman has a recessive genetic condition but neither of her parents has the condition.Which one of the following could not be true? Answer: In order to have the condition,…

A test is developed to detect a certain medical condition. The test is not perfect, and sometimesgives incorrect results. The behaviour of the test on 1000 randomly selected members of…

Graphene is a new material composed of carbon atoms arranged in tightly bound hexagons just one atom thick.The diagram shows a simplified structure of graphene.Considering its structure, which of the…

In order to function, the cells of the brain need large amounts of energy. Any reduction in thefunction of these cells can have serious consequences for the body. For example,…

The diagram shows part of a glass structure. PQRS is a horizontal square with sides of 1 metre, and point X is 4 metres vertically above P. What is the…

The displacement / time graph shown represents a wave of wavelength 1.5 cm. What is the speed of the wave? Answer: Period = 2.0 s so frequency = (1 /…

An organic compound is found to contain 6 parts of carbon, 1 part of hydrogen and 8 parts ofoxygen by mass.6 g of a gaseous sample of the compound would…