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___________________________________________________________________________ PHYSICS SCIENCE Paper 1 (Two hours) Answers to this Paper must be written on the paper provided separately. You will not be allowed to write during the first 15 minutes. This time is to be spent in reading the Question Paper. The time given at the head of this paper is the time allowed for writing the answers. ___________________________________________________________________________ Section I is compulsory. Attempt any four questions from Section II. The intended marks for questions or parts of questions are given in brackets [ ]. ___________________________________________________________________________ SECTION I (40 Marks) Attempt all questions from this Section. Question 1 (a) Mention two factors on which the internal resistance of a cell depends. (b) Name two safety devices which are connected to the live wire of a household electrical circuit. Give one important function of each of these two devices. (c) A current is passed through a steel wire, which gets heated, to a dull red. Then half the wire is immersed in cold water. The portion out of the water becomes bright. Why? (d) Why should the core of a transformer be laminated? (e) Which coil of a step-up transformer is made thicker and why? Question 2 (a) A device is used to transform 20 V A.C. to 200 V A.C. (i) What is the name of the transformer? (ii) Name the principles on which it works. (b) Define the term Heat capacity and state its SI unit? (c) What is the principle of method of mixtures? What is the other name given to it? (d) Why do sandy soils, get heated up quickly as compared to wet soils? (e) Which of the two, 1 g of ice at 0o C or 1 g of water at 0o C contains more heat? Give reason for your answer. Question 3 (a) Some ice is heated at a constant rate, and its temperature is recorded after every few seconds, till steam is formed at 100o C. Draw a temperature -time graph to represent the change. Labels the two phase in your graph. (b) Name the rule to determine the direction of (i) Magnetic field produced around a current carrying conductor. (ii) Force experienced by a straight conductor carrying current placed in a magnetic field which is perpendicular to it. 1 ICSE (Grade : X) | PHYSICS (SCIENCE Paper-I) | Pre Board Exam-II [2] [2] [2] [2] [2] [2] [2] [2] [2] [2] [2] [2] (c) (d) (e) An electrical gadget can give an electric shock to its user under certain circumstances. Mention any two of these circumstances. A piece of ice of mass 40 g is dropped into 200g of water at 50 oC. Calculate the final temperature of water after all the ice has melted. How is a cathode ray beam affected while passing through a magnetic field and an electric field? Question 4 (a) State briefly two uses of a cathode ray tube. (b) Give one difference between a chemical change and a nuclear change. (c) What will an alpha particle change into when it absorbs (i) one electron (ii) two electrons? (d) A radioactive substance is oxidized. Will there be any change in the nature of its radioactivity? Give a reason for your answer. (e) Why is a cathode ray tube evacuated to a low pressure? [2] [2] [2] [2] [2] [2] [2] [2] SECTION II (40 Marks) Attempt any four questions from this Section Question 5 (a) The potential difference between the terminals of a cell in an open circuit was 2.2 V and when it was connected through a resistance of 5 ohm, the potential difference fell to 1.8 V. Find the internal resistance of the cell. (b) A battery of emf 3 V sends a current of O.5 A through a wire. Calculate (i) the resistance of the wire. (ii) the heat energy produced in one minute. (c) An electric bulb rated 220 V, 60 W glows when connected with 220 V mains. (i) Find the resistance of the filament of the bulb. (ii) Another identical bulb is connected in series with the first one and the system is connected across the 22 V mains. Draw a diagram to show the arrangement and find: a) the rate of conversion of energy in each bulb, and b) toatal power consumed. Question 6 (a) Calculate the amount of heat given out while 400 g of water at 30 C is cooled and converted into ice at -2 C. Specific heat capacity of water = 4200 J/kg K Specific heat capacity of ice = 2100 J/ kg K Specific latent heat of fusion of ice = 336000 J/kg b) A body of mass "m1" of a substance of specific heat capacity cl , at a temperature t1 is mixed with another body of mass "m2" of specific heat capacity "c2" at a lower temperature t2. Deduce an expression for the temperature of the mixture t3. (c) Draw a labelled diagram of an alternating current generator. Write the function of its two main parts. 2 ICSE (Grade : X) | PHYSICS (SCIENCE Paper-I) | Pre Board Exam-II [3] [3] [4] [3] [3] [4] Question 7. (a) Calculate the equivalent resistance between the points A and B for the following combination of resistors: [3] (b) (i) (ii) (c) In the figure below, A,B,C are three ammeters. The ammeter B reads 0.5 A. (All the ammeters have negligible resistance Calculate: [4] (i) (ii) Question 8 (a) (i) (ii) (b) (i) What is an Ohmic resister? Two copper wires are of the same length, but one is thicker than the other. (1) Which wire will have more resistance? (2) Which wire will have more specific resistance? [3] the readings in the ammeters A and C. the total resistance of the circuit. Why is tungsten filament used in the bulb? Why are thick wires used in the leads of an electric radiator? Draw a graph of potential difference (V) versus current (I) for an ohmic resistor. 3 ICSE (Grade : X) | PHYSICS (SCIENCE Paper-I) | Pre Board Exam-II [3] (c) (ii) How can you find the resistance of resistor from this graph? (iii) What is a non-ohmic resister? [3] First resistors of different resistances are connected as shown in the figure> A 12 V battery is connected to the arrangement. Calculate: [4] (i) the total resistance in the circuit. (ii) the total current flowing in the circuit. Question 9 (a) What is background radiation? How can you detect it? (b) (i) What is meant by radioactivity? (ii) What is meant by Nuclear waste? (iii) Suggest one effective way for the safe disposal of nuclear waste? (c) In what ways are the effect produced by electric and magnetic fields produced on an electron beam different? 4 ICSE (Grade : X) | PHYSICS (SCIENCE Paper-I) | Pre Board Exam-II [3] [3] [4]
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