Answering Questions Technique Physics SPM Paper 3

Answering Question Technique Physics SPM (4531/3) Paper 3 (40 marks) Time: 1 1/2 hours Section A [28 marks] (2 questions. Answer all Questions from this section. Time suggested for section A is 60 minutes) Section A -Question 1 (16 marks) a). Identify / State variables (3 marks) b). Data tabulation (7 marks) c). Drawing graph

(5 Marks)

d). State relationship between responding variable and manipulative variable based on graph (1 marks) a). Identify / State variables Manipulative Variable: Physical quantity which its value can be fixed by the experimenter before carry out experiment Responding Variable: Physical quantity that change its value in respond to the changes Fixed Variable: Physical quantity that is set to remain constant through out the experiment. e.g. Manipulative variable: Length, l of the pendulum Responding variable: Period of oscillation, T Constant Variable: Mass of the bob/Number of oscillation

b) Tabulation of data in a table (Section A Question1 ) Tabulate results for all values of l, T and T2 in the space provided On the graph paper provided, plot a graph of T2 against l

Diagram 1.1 l = 30.0 cm t =_____ s T= _______s T2 =_____s2

Diagram 1.2 l = 40.0 cm t =_____ s T= _______s T2 =_____s2

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Marking Criteria For Table 1. Shows a table (e.g. which have l, T and T2 correctly in the table) 2. State the correct unit of l/cm, T/s and T 2/s2 3. All values of manipulative variable, l are correct 4. All values of responding variable, T are correct 5. All values of derived variables, T2 are correct 6. All values of responding variable T are consistent in decimal places 7. All values of derived variables, T2 are consistent in decimal places ( 7 √ = 7 marks ) c) Drawing of Graph from data in table (Section A -Question 1)- 5 marks

Marking Criteria For Graph 1. Label Y -axis and X- axis correctly 2. States the unit at the axes correctly 3. Both axes with the even and uniform scale 4. 5 points correctly plotted 5. A smooth best straight line 6. Minimum size of the graph is 4(base) x 5 (height) squares of 2 x 2 cm (1/2 the size of graph paper) Number of √ 6 5 3-4 2

Score 5 4 3 2 2

1 1 Tips For Plotting A Good Graph • If the graph plotted appear an abnormal point, please check • Follow instruction for plotting graph, if T2 against l ,T2 must be in the Y axis (If otherwise marks for labeling will be deducted) • As far as possible start your graph from the Origin, if not will have problem in answering in the following section • For finding the gradient draw a triangle as big as possible, i.e. using the whole graph and label the base and height • Both axes must be label with symbol of quantity and unit d) State relationship between manipulative variable and responding variable(Section A Question 1 ) 1. ………. is directly proportional to………… ( A straight line graph passes through the origin) 2. ……….. is linearly proportional to ……….. [ straight line intercept at Y axis (positive gradient)] 3. ……….. is decreasing linearly with …………… [ A straight line intercept at Y axis (negative gradient)] 4. …………… is inversely proportional to ………… [ A curved graph with negative gradient ] 5. When ……….. increases, ………. increases [ A curved graph with positive gradient] (Avoid using T2 increases l increases instead use T2 linearly proportional to l or increases linearly (least advisible). Other example exponential proportional, inversely proportional, directly proportional.) Section A-Q 2- Questions On Graph (12 marks). Analysis of graph given ( 10 or 11 marks)

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(a). Find the length submerged when container is empty Answer: 5 cm (b).If l is 17.25 cm, what is the weight of lead shots Answer: 0.25 N

(c). The relationship between l & w is given by the equation. W=[ρ/1000]l-0.1 Find ρ of liquid (g = 10 m-2)

Answer: m= [(0.4-0.1)N]/[(*0.25-0.10)m]=2 Nm-1 (* Convert unit to m because g given is in ms-2) equate m=2 with ρg/1000 from the equation therefore, 2 = ρg/1000 ρ= 2 x 1000 / 10 4

ρ= 200 kg / m3 Allocation of marks a) State relationship of variables (1 mark) State relationship of variables. e.g.: What happens to l as W increases ? b). Calculation of gradient, values (by extrapolation or interpolation), derived values, determine values based on the graph given (10 marks) (Show on the graph how you obtain the gradient. Substitute the gradient into the equation to get ρ) [Gradient:- Triangle almost 1/2 the size of the graph] Extrapolation-values extend off-side the range. Interpolation- value determine on the graph (one quantity correspond to another) Show on the graph, how to determine the value of W if value of l is 17.25 cm.(Interpolation) What is the length submerged when container is empty (Extrapolation) c). Precautions (1 mark) e.g. State one precaution that can be taken to improve the accuracy of the readings in this experiment. Precautionary Steps For Investigation Experiment No. Type of experiment involving 1 Light

2.

Spring

3.

Electric

4.

Heat

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Measuring instrument involving ammeter, voltmeter, metre rule……

Precaution that can be taken a. experiment must be carried out in a darkened room b. lens, object and screen must be in line c. make sure that the line of vision is perpendicular with the scale of metre rule while reading the scale to avoid parallax error a. make sure the spring is not loaded beyond the elastic limit (that is the spring returned to its original length when the load is taken off) b. make sure that the line of vision is perpendicular with the scale of metre rule while reading the scale to avoid parallax error a. make sure that all connections are secure/ tight to avoid current leakage b. The switch should be off after the readings are taken to prevent wires from heating up/ resistance increases c. make sure that the line of vision is perpendicular with the scale of metre rule while reading the scale to avoid parallax error a. liquid is stirred constantly so that temperature rises evenly b. Aluminium block is wrapped with insulating material to avoid heat loss c. thermometer bulb must be smeared with oil to give better thermal contact with the block d. make sure that the line of vision is perpendicular with the scale of metre rule while reading the scale to avoid parallax error a. make sure that the line of vision is perpendicular with the scale of metre rule while reading the scale to avoid parallax error b. Take into account zero error of the instrument

*Unacceptable answer: Avoid parallax error (without explanation) 5

Example: Question 2 On Section A ( Question 2 -Sectioon A, Year 2008)

(a) (i) State relationship between a and h Answer : a is directly proportional to h (ii) Determine value of a when h= 0.30m Answer: a= 1.5 ms-2 (b) Calculate the gradient, m of the graph, Show on the graph how you determine m Answer: m = (1.0-0.5)/(0.20-1.10) = 5.0 s-2 (c) m is given by the formula m = g / l , where g is the gravitational acceleration and l is the length of the inclined plane. In the experiment, l = 2.0 m. Calculate the value of g Answer: m= g/l 5 = g/2 therefore g = 5 x 2 = 10 ms-2 (d) Student repeats experiment. Using inclined plane of l = 1.5 m and raised end to height h = 0.10 m. Using the formula a = (g/l )x h, and the value of g in (b), calculate a Answer: a= (g/l) x h =(10/1.5 )x 0.10 = 0.67 ms-2 6

Section B [12 marks] (Answer any one question from this section. Time suggested for section B is 30 minutes) Question on Experiment Framework a). Identify variable : Highlight and relate the physical quantities to the closest terms. Pay special attention to quantities which vary e.g. Q3 Section B P3 SPM 2008 Diagram 3.1 and 3.2 show a worker pushing a wheelbarrow on a soft ground. He notice that the tyre sinks deeper into the ground when the wheelbarrow is loaded

Quantities which are varied : Weight on wheelbarrow (Related variable = Force), Tyre sinks deeper (Related variable = Pressure) b). Writing Technique : i) Inference (1 mark) Based on observation-An initial interpretation or explanation concerning the observation. It can be true or false. Normally use terms like depends on, influenced by affected by (Observation- Action involve senses in gathering information about an object or event) Manipulative variable affects the responding variable Responding variable is depends on the manipulative variable Responding variable is influenced by the manipulative variable e.g: Bigger force causes the tyre sink deeper Bigger pressure causes the tyre to sink deeper Pressure exerted on the ground by the tyre is dependent on the force acted on the tyre (not encourage to write inference same as hypothesis) ii) Hypothesis (1 mark) Hypothesis: A statement of an expected outcome that usually states the relationship between two variables which will undergo a direct experiment test When the manipulative variable increases/decreases the responding variable increases/ decreases e.g : The greater the force, the greater the pressure • Hypothesis only refer to the experimental frame work not the diagram given (Not encourage writing hypothesis base on diagram)

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iii) Aim (1 mark) To study/investigate the relationship between manipulative variable and the responding variable e.g. To investigate the relationship between force and pressure iv) Types of variables: Manipulative, Responding, Fixed (Only one fixed variable needed) (2 marks) Variable: Physical quantity that can be varied in an experiment ( State the variables that can be measured ) Encourage to write operational definition for variables. e.g. Pressure is the Depression make on the plasticine by the mass. Force is taken as the Mass drop from the height of 50 cm) e.g.: Manipulated variable: Mass of object (1 mark) Responding variable: Depth of depression Constant variable : Height of object drop (Variable must be related with the experiment and the common one, e.g.:the Period of oscillation, not encourage to write time for 10 oscillations) v) List of apparatus and material. (1 mark) State all the important apparatus used e.g. Plasticine, weight/object of 50g, 100g, 150g, 200g and 250g and metre rule

No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

Physical Quantity Length/Distance/Depth/Height/Extension Mass Time of oscillations/Period Temperature Current Force Diameter of wire Velocity/Acceleration Gas Volume Gas Pressure Potential difference Magnetic field strength Wavelength Control current Water volume Resistant of wire

Measuring Apparatus Meter rule Lever balance/Triple beam balance Stopwatch Thermometer Ammeter/Galvanometer Spring balance Micrometer screw gauge Ticker timer and ticker tape Syringe Bourdon gauge Voltmeter Number of nails attracted Meter rule Rheostat Measuring cylinder/Beaker Ammeter and Voltmeter ( R = V/I )

vi). Arrangement of apparatus: (1 mark) Draw a fully labeled diagram

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c). Method/Procedure: (Three important statements) (3 marks) i). Start the experiment with manipulative variable: ……….. (a practical value) ii). Responding variable is measured and recorded (ways and how?) iii). Repeat the experiment 4 times with different values of manipulated variable 20, 30, 40, 40 g (mention all the remaining) e.g. 1. Plasticine with uniform thickness is placed on the table 2. Drop 50 g object on the from a fixed height h (object must be uniform size like square shape not round) 3. Remove the weight and measure the depth, d of the depression on the plasticine using metre rule 4. Repeat the steps by using weights of 100 g, 150 g, 200 g, and 250 g d). Tabulation of data (1 mark)

Manipulated Variable / unit

Responding Variable/ unit

--State All the Values---

---blank---

Mass, m / g 50 100 150 200 250

Depth, d / cm

e). Analysis of data: (State and sketch a graph) (1 mark) State : A graph of responding variable against manipulated variable is plotted or show the sketch with axes labeled ( can without the real shape of the graph) Resp. Var /unit

Manip. Var/ unit 9

* Do not describe irrelevant experiment. Maximum mark for irrelevant experiment is only 4 will lose 8 marks (aspects may be awarded marks are : inference, hypothesis or aim, tabulation of data and analysis of data ) Example:

Different mass, different final length of spring

DO NOT describe experiment on mass and period of oscillation

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