Turn over 7 10 A detector is placed 30 cm from a gamma source, the count rate is 64 counts per minute. The detector is then placed 60 cm from the source. The background rate is presumed to be a constant 24 counts per minute. Which of the following gives the expected counts per minute? A 16 B 32 C 34 D 44 (Total for Question 10 = 1 mark) 11 A cup contains 180 g of black coffee at a temperature of 82 °C. 68 g of milk at a temperature of 2.7 °C is added to the coffee. An ideal temperature range for drinking coffee is said to be 50 °C to 60 °C. Deduce whether the coffee will be within the ideal temperature range when the milk is added. initial temperature of milk = 2.7 °C specific heat capacity of black coffee = 4.2 × 103 J kg−1 K−1 specific heat capacity of milk = 3.9 × 103 J kg−1 K−1 (3) .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. .................................................................................................................................................................................................................................................. (Total for Question 11 = 3 marks)