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o Bachani Nagar Malad (E) o Ashok Nagar Kandivli (E) o Thakur Complex Kandivli (E) PRELIMINARY EXAMINATION 2018-2019 Grade : X Date 11/12/2018 : Subject : Physics ICSE Marks: 80 Time : 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. This paper consists of 6 printed pages Attempt all questions from Section I and any four questions from Section II. The intended marks for questions or parts of questions are given in brackets [ ]. 2 Hrs Section I (40 Marks) Attempt all questions from this section Question 1 a) (i) Define centre of gravity. (ii) Fill in the blank with appropriate word: The centre of gravity of a hollow cone of height h is at a distance______ from its base. [2] b) Give the energy conversion while (i) the lighting of a kerosene lamp (ii) Charging of a battery [2] c) A sound produced on the surface of a lake takes 4.5 s to reach a boatman. How much time will it take to reach a diver inside water at the same distance if speed of sound in water is 4.5 times the speed of sound in air? [2] d) Write any two factors affecting the refractive index of a medium. [2] e) In India, at what voltage and frequency is the electric power generated at the power generating station? [2] Question 2 a) How does the speed of light in glass changes on increasing the wavelength of light? Name the subjective property of light related to its wavelength. [2] b) A sound wave passes from one medium to another. Name one property of this wave (i) which changes (ii) which does not change. [2] c) How is MA related to VR for (i) an ideal machine (ii) a practical machine [2] d) Mention how specific resistance of the following changes with temperature: (i) Semiconductors (ii) constantan Physics/Grade X/ICSE/Preliminary Examination/ Page 1 of 6 [2] CAT/LD/2018-19 e) How can we increase the magnetic field strength of an electromagnet? [2] Question 3 a) What information about the nature of image (i) real or virtual, (ii) erect or inverted, do you get from the sign of magnification + and . [2] b) What kind of energy change takes place when a magnet is moved towards a coil having a galvanometer between its ends? Name this phenomenon. [2] c) How does the (i) average kinetic energy and (ii) average potential energy of molecules of substance change during its change in phase at constant temperature on heating? [2] d) How does the temperature and concentration of the electrolyte affect the internal resistance of a cell ? [2] e) An engine can pump 30,000 litres of water to a vertical height of 45 m in 10 min. Calculate the work done by the machine and the power. (Density of water=103 kg m-3, 1000 litre =1m3, g = 9.8ms-2) [2] Question 4 a) Name the physical quantity which is measured in calorie. How is it related to the SI unit of that quantity? [2] b) An object is kept inside water ( =4/3) when viewed from air in a vertical direction, appears raised by 2 mm. Find the depth of coin in water. [2] c) The stem of a vibrating tuning fork is pressed against a table top. (i) Will it produce an audible sound? (ii) What type of vibrations are set at the table top? [2] d) Define specific resistance of a material and write its SI unit. [2] e) A radioactive nucleus AXZ first emits a beta particle and then an alpha particle and the resulting nucleus is represented by PYQ. What are the values of P and Q in terms of A and Z? [2] Section II (40 Marks) Attempt any four questions from this section Question 5 a) Distinguish between static and dynamic equilibrium. Give one example of each. [3] b) How much energy is gained by a box of mass 20 kg when man (i) carrying it wait for 5 minutes for a bus? (ii) runs carrying the box with a speed of 3m/s to catch the bus? (iii) raises the box by 0.5m in order to place it inside the bus? Physics/Grade X/ICSE/Preliminary Examination/ Page 2 of 6 [3] CAT/LD/2018-19 c) Figure shows a block and tackle system of pulleys used to lift a load. (i) How many strands of tackle are supporting the load? (ii) Draw arrows to represent tension in each strand. (iii) What is the mechanical advantage of the system? (iv) When load is pulled up be a distance 1 m, how far does the effort end move? [4] Question 6 a) A lens forms the image of an object placed at a distance 15cm from it, at a distance 60 cm in front of it. Find: (i) the focal length, (ii) the magnification, and (iii) the nature of image. [3] b) State any three common properties of an electromagnet waves. [3] c) (i) When an illuminated object is held in front of thick glass mirror 4 images are seen, of which the second image is brightest Give reasons. (ii) Light of single colour is passed through a liquid having a piece of glass suspended in it. In changing the temperature of liquid, at a particular temperature the glass piece is not seen. (1) When is the glass piece not seen? (2) Why is the light of single color used? [4] Question 7 a) (i) Displacement-distance graph of two sound waves A and B, travelling in a medium, are as shown in the diagram below. Study the two sound waves and compare their amplitudes and wavelengths (ii) State any one necessary condition for hearing a distinct echo. Physics/Grade X/ICSE/Preliminary Examination/ Page 3 of 6 [3] CAT/LD/2018-19 b) (i) Why are the stringed instruments like guitar provided with hollow sound box? (ii) What is the safe limit of sound in decibel for human ear? [3] c) (i) A boy stands 60 m in front of a tall wall and claps. The boy continues to clap every time an echo is heard. Another boy finds that the time taken between the 1st and 51st clap is 18 seconds. Calculate speed of sound. (ii) The diagram above shows a wire stretched over a sonometer. Stems of two vibrating tuning forks A and B are touched to the wooden box of the sonometer. It is observed that the paper rider (a small piece of paper folded at the centre) present on the wire flies off when the stem of vibrating tuning fork B is touched to the wooden box but the paper just vibrates when the stem of vibrating tuning fork A is touched to the wooden box. (1) Name the phenomenon when the paper rider flies off. (2) Why does the paper rider fly off when the stem of tuning fork B is touched to the box? [4] Question 8 a) In the adjacent circuit, find the effective resistance between the points A and B. [3] b) A power circuit uses a cable having three different wires. (i) Name the wires of the cable. (ii) To which of the two wires should the heating element of an electrical geyser be connected. (iii)To which wire should the metal case of the geyser be connected. Physics/Grade X/ICSE/Preliminary Examination/ Page 4 of 6 [3] CAT/LD/2018-19 c) (i) The diagram in figure shows a current carrying loop passing through a sheet of cardboard at the M and N. Draw three magnetic field lines on the cardboard, one for each points M and N, and one at the center of loop. Draw the arrows to show the direction of magnetic field lines. (ii) State any two points of difference between A.C motor and D.C generator. [4] Question 9 a) (i) A slab of ice at 0 oC is constantly heated till it gets converted into steam. Draw the graph showing the change in temperature with time. Label the various phases of graph properly. (ii) Lead has a specific heat capacity of 130 J kg 1 K 1.Explain what is meant by this statement. [3] b) (i) Give reason why ice cream at 0 oC appears colder than water at 0 oC when consumed. (ii) State the effect of presence of impurity on melting point of the ice. [3] c) In a laboratory experiment for finding the specific latent heat of ice, 100 g of water at 30 C was taken in a calorimeter made of copper and mass 10 g. When 10 g of ice at 0 C was added to the mixture and kept within the liquid till the ice melted completely, the final temperature of the mixture was found to be 20 C. (i) What is the total quantity of water in the calorimeter at 20 C. (ii) Specific heat capacities of water and copper being 4.2 J g-1 C-1 and 0.4 J g-1 C-1 respectively, what quantity of heat would each release in cooling down to 20 C from the initial stage? (iii) Write an expression for the heat gained by ice on melting. (iv) Calculate the value of the latent heat of fusion of ice from the data discussed above. [4] Question 10 a) Arrange , , and rays in ascending order with respect to their: (i) Penetrating power. (ii) Ionising power. (iii) Biological effect Physics/Grade X/ICSE/Preliminary Examination/ Page 5 of 6 [3] CAT/LD/2018-19 b) (i) Define radioactivity. (ii) What happens inside the nucleus that causes emission of beta particles? (iii) Express the above change in the form of equation. [3] c) (i) A mass of lead is embedded in a block of aluminum (2 mm thick). Radiations from a radioactive source incident on the side of the block affects the fluorescent screen placed beyond the block. The affect appears in the form of shadow on the screen. The shadow of the block of aluminum is fainter than the shadow of lead. Give the reason for this difference. (ii) Explain why nuclear fusion is not possible at ordinary temperature? [4] ***********************THE END*********************** "Eliminate Measles and Rubella, be an MR warrior." Physics/Grade X/ICSE/Preliminary Examination/ Page 6 of 6 CAT/LD/2018-19
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