4 3 A student carried out an experiment with a pendulum hung from a fixed support. The fixed support was a distance h above floor level as shown. h d fixed support string bob floor As the student was unable to measure the length of the pendulum directly, she measured the distance d from the bob to the floor. (a) To determine the period T of the pendulum, the student used the following method: • release the bob from its highest position and start a stopwatch • stop the stopwatch when the bob reaches the same position again. Criticise the student’s method for measuring the period. (2) .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................. 5 Turn over (b) The student used her data to plot a graph of T 2 against d as shown below. 0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 8.0 9.0 10.0 11.0 12.0 13.0 14.0 d / m T 2 / s2 Determine a value for the acceleration due to gravity g. (5) .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................... .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. g = ....................................................... (Total for Question 3 = 7 marks) 6 *4 Radium is a radioactive element. The most common isotope of radium has a half-life of almost two thousand years. A sample of radium can remain at a higher temperature than its surroundings for a long period of time. Explain how a sample of radium is able to release significant amounts of energy over a long period of time. 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(Total for Question 4 = 6 marks) 7 Turn over BLANK PAGE