P H Y S I C S Half Yearly Exam Specimen Paper

Transcription

1 P H Y S I C S Half Yearly Exam Specimen Paper Form 3 Time: 2 hrs Name: Class: Answer all questions on the exam paper. In calculations you are advised to show all steps in your working. The use of scientific calculators is allowed. Marks are allotted for good presentation and well-labelled diagrams. Section A Answer all questions. 1. This question is about measurements. (a) Fill in the missing information: Quantity Symbol S.I. Unit Instrument Mass Time Length Volume of a liquid (b)complete the following: V kg Stopwatch (i) The mass of a bag of apples is 3540g. Its mass in kg is kg. (ii) The volume of a large barrel of wine is cm 3. Its volume is m 3. (2) (9) (1) (c) What error do we avoid when measuring: (i) time: (1) (ii) length: (1) Page 1 of 10

2 2. This question is about density. A rap star had his jewellery stolen while on tour in Ireland. This included a gold ring. The items were found later on. (a) Your job in the crime lab is to find out whether these items are real or an imitation with respect to their density. (i) List of apparatus required is: measuring cylinder with water, the gold ring and the. (1) (ii) What are the two measurements that you would need to take to be able to find the density of the objects? (2) (iii) Using the above apparatus, describe what method you would use to find the density of the gold ring. (5) (iv) Give one precaution you would take when reading the volume of water inside the measuring cylinder. (1) Page 2 of 10

3 (v) Initially 50 cm 3 of water was poured into the measuring cylinder. On dropping the gold ring the water level rose to 55 cm 3. What is the volume of the gold ring? (1) (vi) The mass of the gold ring is 52.5g. Find its density. (2) (vii) The density of pure gold is 19.3 g/cm 3. Is the ring made of gold or is it an imitation? (1) (viii) A plastic ring of density 0.75 g/cm 3 is dropped in water of density 1g/cm 3. Will the plastic ring sink or float in water? (1) Page 3 of 10

4 3. This question is about the reflection of light. object (a) Maria looks at an object in a mirror. (i) Complete the ray diagram showing the path taken by the two rays. Show the position and size of the image obtained. Draw the two normals for each ray. (4) (ii) Mention one property of the image obtained. (1) (b) The figure below represents a ray of light striking and being reflected by a plane mirror. O Complete the following: (i) YO is the ray. (1) (ii) Angle B is the angle of. (1) (iii) If angle A is equal to 30, the value of angle B is equal to while the value of angle C is equal to. (2) Page 4 of 10

5 4. The diagram below shows a light ray falling on a perspex block. A B Air Perspex Glass Air (a) Complete the diagram to show what happens to ray AB as it passes from air to Perspex and from perspex to air. Do not forget to draw your normals. (3) (b) Indicate clearly on the diagram: (i) The angle of incidence of the ray on the perspexblock by marking it with an i ; (1) (ii) The angle of refraction of the ray after it emerges from the Perspex block, by marking it with an e ; (1) (iii) What can you say about the direction of the incident ray and the direction of the emergent ray (the ray of light that leaves the perspex block)? (1) (c) The refractive index for diamond is 2.5. If the speed of light in air is 3x10 8 m/s, calculate the speed of light in the diamond. (3) Page 5 of 10

6 5. (a) Andrew shone a torch beneath the water at three different angles as shown below. The critical angle for water is 49. (i) Complete the path followed by ray A. (1) (ii) Complete the path followed by ray B. (1) (iii) One can say that ray B has been. (1) (iv) Complete the path followed by ray C. (1) (v) One can say that ray C has been:. (1) (vi) Explain why the ray C follows that path? (2) _ (c) The diagram below shows a fibre optic X Angle X is than the critical angle so that the ray travelling through the fibre optic undergoes and no light escapes from the sides of the fibre optic. Fibre optics are nowadays used both in endoscopes for medical purposes and instead of wires for communications. (5) Page 6 of 10

7 6. Sophie dropped some plasticine into the pool. It is found at the bottom of the pool as shown in the figure below. (a) In the above diagram complete the path followed by the two rays into the air into Sophie s eyes and show how Sophie sees the plasticine closer to the surface that it actually is. Do not forget to draw your normals. (4) (b) Does Sophie see a real or virtual image?. (1) (c) The refractive index of water is The pool has a depth of 1.5m. How far below the surface of the water does the ring appear to be? (3) Page 7 of 10

8 7. In the diagram below one can see the earth rotating around the sun. (a) Why does the earth keep rotating around the sun? (1) (b) As can be seen in the diagram above the earth experiences different seasons. Why is this? (2) (c) In position C the Southern hemisphere experiences summer. (i) In what position would the southern hemisphere be six months later? (1) (ii) What season would it experience? Explain why? (2) (d) Which planet in our Solar System has the longest year? Give a reason for your answer. (2) Page 8 of 10

9 (e) In 2006, the International Astronomical Union (IAU) developed a new definition for planets and Pluto was no longer considered to be a planet. Why is this? (2) (f) The Hubble telescope can be found orbiting the earth. It has provided us with a lot of valuable information about outer space. What advantage does the Hubble telescope offer over other telescopes found in observatories on Earth? (2) Page 9 of 10

10 8. This question is about helical springs. Sarah hangs a light helical spring vertically from a fixed position. She uses a light pointer attached to its lower end, to take readings on a vertical scale when masses of various sizes are attached. She tabulates the scale readings of the pointer for the different masses attached. Mass attached (kg) Scale reading (mm) Extension (mm) (a)calculate the extension for the missing measurements in the table above. (1) (b) Use these results to plot a graph of extension e (mm) on the y-axis (vertical) against mass m (kg) on the x-axis. (4) (c) From the graph you have just plotted, what information do you get about the relationship between the extension and the mass, in the region from no load up to a load of 0.4kg? (2) (d) Give the name of the law describing this relationship. (1) (e) Above 0.4kg, the elastic limit had been exceeded. Explain what happens to the spring above this point? (1) (f) Name one precaution required to obtain accurate results during such an experiment. (1) End of Paper Page 10 of 10