1. In an experiment, data were collected on the variation of specific heat capacity of water with temperature. The graph of the plotted data is shown.
(a) Draw the line of best-fit for the data.
(b) (i) Determine the gradient of the line at a temperature of 80°C.
(ii) State the unit for the quantity represented by the gradient in your answer to (b)(i).
(c) The uncertainty in the values for specific heat capacity is 5%.Water of mass (100±2) g is heated from (75.0±0.5)°C to (85.0±0.5)°C.
(i) Calculate the energy required to raise the temperature of the water from 5°C to 85°C.
(ii) Using an appropriate error calculation, justify the number of significant figures that should be used for your answer to (c)(i).
2. An electrical circuit is used during an experiment to measure the current I in a variable esistor of resistance R. The emf of the cell is e and the cell has an internal resistance r.
A graph shows the variation of 1/I with R
(a) Show that the gradient of the graph is equal to 1/e.
(b) State the value of the intercept on the R axis.
3. A student is running an experiment to determine the acceleration of free-fall g. She drops small metal ball from a given height and measures the time t taken for it to fall using an electronic timer. She repeats the same experiment several times.
(a) Suggest a reason for repeating the experiment in the same conditions.
(b) With the collected data she determines the value of g to be (10.4±0.7) ms–2.Researching scientific literature about the location of her experiment she finds the value of g to be (9.807±0.006) ms–2. State, with a reason, whether her xperiment is accurate.