Physics (AS & A Level) · Feb / March 2016 · Paper 52 · Question 2
9702
As printed in the paper
The question as text
A student is investigating the heating of metal blocks immersed in water. A 100 g metal block is added to 250 cm3 of water in an insulated beaker. The water is heated by an electrical heater as shown in Fig. 2.1. thermometer metal block heater insulation to power supply water Fig. 2.1 A stopwatch is used to measure the time t for the temperature of the water and metal block of mass mm to change by 20 °C. The experiment is repeated by adding additional 100 g metal blocks to the water. It is suggested that t and mm are related by the equation Pt = mmcmΔθ + mwcwΔθ + k where P is the constant power of the heater, cm is the specific heat capacity of the metal, cw is the specific heat capacity of water, Δθ is the temperature change, mw is the mass of the water and k is a constant.
Read automatically from the paper; the printed page above is exact.
Show the answer and mark scheme
2(a)[1]
Gradient = m c P θ ∆ y-intercept = w w m c k P θ ∆ +
2(b)[2]
T1 Column heading mm / g 100 200 300 400 500 600 U1 From ± 10 to ± 60
2(c)(i)[2]
G1 Six points plotted correctly U2 Error bars in mm plotted correctly
2(c)(ii)[2]
G2 Line of best fit G3 Worst acceptable straight line. Steepest or shallowest possible line that passes through all the error bars.
2(c)(iii)[2]
Gradient of the line of best fit; the triangle used should be at least half the length of the drawn line. (1)
Absolute uncertainty: gradient of line of best fit − gradient of worst acceptable line, or ½(steepest worst line gradient − shallowest worst line gradient). (1)
2(c)(iv)[2]
y-intercept of the line of best fit. (1)
Absolute uncertainty: y-intercept of line of best fit − y-intercept of worst acceptable line, or ½(steepest worst line y-intercept − shallowest worst line y-intercept). (1)
2(d)(i)[3]
cm in the range 470 to 530 and given to 2 or 3sf k =y-intercept x P – mwcw∆θ k =y-intercept x 50 – 21000 Units for cm and k
2(d)(ii)[1]
Percentage uncertainty in cm: (Δgradient/gradient + 5/50 + 0.5/20) × 100 = (Δgradient/gradient + 12.5%). (1)
Make a free account to save your answers and see your weak topics and ask the AI why a wrong answer is wrong.