BMAT 2007-S2

The table shows the percentages of some substances measured in fluid taken from a human kidney.

Element x is in the second period of the Periodic Table. An atom of element y has six more protons than an atom of element x.

A detector of radioactivity shows background radiation to be 20 counts per minute with no radioactive sources nearby. A radioactive source which emits alpha particles and beta particles is brought very close to the detector and the detector reading increases to 280 counts per minute. A sheet of paper is then placed between the source and the detector, and the detector reading drops to 60 counts per minute.

The equation connects the variables A, x, y, z, P and Q.

The following changes are made:

x and y are both increased by 50 %

z is decreased by 20 %

P is doubled and Q remains the same.

The three statements below are about exhaling.

1. The ribs swing down and inwards during exhaling.

2. The diaphragm muscles contract during exhaling.

3. The pressure in the lungs increases during exhaling.

The oscillation period, t, for a spiral spring (weight w, radius R made from wire length l, radius r with a modulus of rigidity n) with a weight W hanging from it is given by:

If such a spring is used to measure the weight, W, of an object we need to rearrange the equation so W is the subject.

A 100 % efficient transformer has 1500 turns on its primary coil. The input to the transformer is 250 V ac. The output current is 10 A and the output power is 0.5 kW.

An oxide of iron has the formula Fe₃O₄ and contains both Fe²⁺ and Fe³⁺ ions.

Which row of the table shows the state of the heart valves when the heart pumps blood to the lungs?

The reaction between lead(II) nitrate solution and potassium iodide solution is shown below:

Pb(NO₃)₂ (aq) + 2Kl (aq) → 2KNO₃ (aq) + Pbl₂ (s)

When the two solutions are mixed in a test tube the height of the lead(II) iodide precipitate formed can be measured.

Below are four statements about thermal (heat) energy.

1. A substance can lose heat energy without its temperature falling.

2. Heat energy can pass through a vacuum.

3. Steam at 100 ^oC has more heat energy than the same mass of boiling water at 100 ^oC

4. When a container of water is cooled near the top, a convection current is set up in the water.

The box and whisker plot shows some information about members of a health club using a walking machine. It shows the number of steps that a group of 30 members did in a period of 10 minutes.

Use this information to find the probability that when 3 of these 30 members are chosen at random, they will all have taken between 850 and 1000 steps.

The diagram shows the bones and leg muscles of a person standing on their toes. The bones and muscles are acting as a lever system.

Which of the following reactions between a Group 1 element and a Group 7 element would be the most exothermic?

Which diagram shows how a ray of white light is refracted by an air bubble in water, and gives the correct relative positions of the red and violet light formed by dispersion?

The two inequalities given below define an area on a graph.

y ≥ x² +3

x ≥ 1/ y

The below diagram shows a family tree of a condition known as nail patella syndrome (NPS).

What volume of steam would be produced from an ice cube of mass 6.00 g if it were heated until it all evaporated?

(A_r values: H = 1; O = 16)

(Take molar volume at room temperature and pressure = 24 dm³)

A heavy uniform bar is in equilibrium in the arrangement shown.

The longest side of a right angled triangle is 6 + √5 units. One of the shorter sides is 3 +2 √5 units.

A patient with leukaemia is being treated with chemotherapy and radiotherapy. The patient is found to have a low blood platelet count and a high percentage of the white blood cells are abnormal.

Some statements about ammonia are given below.

1. Its formula is NH₃.

2. The pH of its solution in water is less than 7.

3. It has a molecular structure.

4. It turns damp blue litmus paper red.

5. It is a liquid at room temperature.

6. It is covalently bonded.

An artery has a length x mm and blood flows steadily through it at V ml per second.

The solid shown below consists of a cylinder topped by a hemisphere of the same radius.

A mixture of equal parts of hexane (bp 68 ^oC) and heptane (bp 98 ^oC) is distilled using a fractionating column.

The temperature of the liquid in the flask and the temperature at the top of the fractionating column are measured.

Which row of the table shows the roles of the female sex hormones in controlling the menstrual cycle?

The position of cobalt in the periodic table is as follows:

Cobalt 60 is a radioactive isotope that decays with the emission of beta and gamma radiation. A beam of radiation from a cobalt 60 source is directed towards a malignant tumour in a patient’s abdomen.

1. The cobalt (₂₇Co) is being converted into nickel (₂₈Ni) as it decays.

2. The tumour is attacked by the gamma radiation.

3. The radiation attacks only the malignant cells.