Physics 9702/33 February/March 2023: question paper and mark scheme

Question

In this experiment, you will investigate the equilibrium of a wooden rod. (a) (i) • Assemble the apparatus as shown in Fig. 1.1 with the nail held securely in the cork. Check that the rod can swing freely. nail cork clamp boss notches L H wooden rod stand bench mass Fig. 1.1 • The height of the nail above the bench is H. Measure and record H. H = …… This height must be kept constant throughout the experiment. • The distance between the nail and the centre of the mass is L. Measure and record L. L = …… [1] (ii) • Assemble the remaining apparatus as shown in Fig. 1.2. Place the string loop in a notch near the mid‑point of the rod. stand pulley string loop string θ plumb line h mass Fig. 1.2 • Adjust the height of the pulley so that the string pulling the rod is parallel to the bench. • The height of the string above the bench is h, as shown in Fig. 1.2. Measure and record h. h = …… • The angle between the plumb line and the rod is θ, as shown in Fig. 1.2. Measure and record θ. θ = …… ° [1] (b) Move the string loop to another notch and adjust the height of the pulley and the position of its stand so that the string pulling the rod is parallel to the bench. Repeat until you have six sets of values of h and θ. Record your results in a table. Include values of sinθ to 3 significant figures in your table. [9] (c) (i) Plot a graph of sinθ on the y‑axis against h on the x‑axis. [3] (ii) Draw the straight line of best fit. [1] (iii) Determine the gradient and y‑intercept of this line. gradient = …… y‑intercept = …… [2] (d) It is suggested that the quantities θ and h are related by the equation sinθ = a h + b where a and b are constants. Using your answers in (c)(iii), determine the values of a and b. Give appropriate units. a = …… b = …… [2] (e) The mass of the wooden rod is M. Calculate M using the relationship – 1 = L + ML a N where N is 200 g. M = …… g [1] [Total: 20] You may not need to use all of the materials provided.

Question

In this experiment, you will investigate the properties of sugar solution. (a) • Assemble the apparatus as shown in Fig. 2.1. screen u0 v torch lens transparent container bench modelling clay Fig. 2.1 • The distance from the screen to the centre of the lens is v, as shown in Fig. 2.1. Adjust the apparatus so that v is approximately 40 cm. Measure and record v. v = …… cm • Switch on the torch and shine the light through the lens. An image of the LEDs in the torch will appear on the screen. • Adjust the distance of the torch from the lens until the image of the LEDs is as sharp as possible. The distance from the front of the torch to the centre of the lens when the image is as sharp as possible is u0, as shown in Fig. 2.1. Measure and record u0. u0 = …… cm [2] (b) (i) • You have been provided with a beaker labelled Sugar Concentration 0.18. Pour the sugar solution into the transparent container until the lens is just covered, as shown in Fig. 2.2. Check that v is still approximately 40 cm. u v sugar solution Fig. 2.2 • Adjust the position of the torch until it shows a sharp image of the LEDs on the screen. Measure and record the distances v and u. v = …… cm u = …… cm [1] (ii) Estimate the percentage uncertainty in your value of u. Show your working. percentage uncertainty = ……% [1] (iii) • The combination of the lens and the sugar solution has a focal length f. Calculate f using the expression vu f= . (v + u) f = …… cm • The sugar solution has a refractive index n. Calculate n using the expression 0.553f n= . 1 + 0.333f n = …… [2] • Pour all the sugar solution back into the beaker labelled Sugar Concentration 0.18. (iv) Justify the number of significant figures you have given for your value of n. …… [1] (c) Repeat (b)(i) and (b)(iii) using liquid from the beaker labelled Sugar Concentration 0.33 to find the refractive index n of this solution. v = …… cm u = …… cm f = …… cm n = …… [3] (d) The sugar concentration in the sugar solution is C. It is suggested that the relationship between n and C is given by n – 1.31 k= C where k is a constant. Using your data, calculate two values of k. first value of k = …… second value of k = …… [1] (e) It is suggested that the percentage uncertainty in the values of k is 20%. Using this uncertainty, explain whether your results support the relationship in (d). …… [1] (f) (i) Describe four sources of uncertainty or limitations of the procedure for this experiment. For any uncertainties in measurement that you describe, you should state the quantity being measured and the reason for the uncertainty. 1 …… 2 …… 3 …… 4 …… [4] (ii) Describe four improvements that could be made to this experiment. You may suggest the use of other apparatus or different procedures. 1 …… 2 …… 3 …… 4 …… [4] [Total: 20]