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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. Attempt all the question from section I and any four questions from question II. The intended marks for questions or part of questions are given in []. SECTION I ( 40 MARKS) Attempt all questions from this section. Question 1 (a) (i) (ii) (b) (c) (d) (e) (a) (b) (i) (ii) (c) (i) (ii) (d) (i) (ii) With respect to a rain drop falling towards the earth answer the following What are the forces acting on it. State the type of equilibrium possessed by it. A constant force of F N acts on a body and displaces it by S m in the direction of the force in a time of t s. Write an expression to calculate (i) Work done (ii) Power developed. A Single movable pulley has an ideal mechanical advantage=2, But an actual single movable has M.A.<2. State two reasons why it is so. Why is the vessel used for measurement of heat is made of a thin sheet of copper? 4680 J of heat energy is absorbed by150 g of a substance to increase its temperature of 10 C to 90 C. Calculate the Specific heat capacity of the substance and express it in SI units. Question 2 A certain quantity of ice at 0 C changes to steam at 100 C on supplying heat energy. Draw a time- temperature heating curve representing this change and also mark the two phase changes in the graph. How does the wavelength of light get affected when light travels from optically rarer to optically denser medium? In a medium other than air if the speed of red light is 2.1x10 8 m/s. will the speed of violet light be lesser or greater than this value? Write an expression to calculate the absolute refractive index of glass in terms of its speed. What is the name given to describe the angle of incidence in the denser medium for which the angle of refraction in the rarer medium is 90 ? Write the nature and characteristics of the image formed by a lens ,given the linear magnification = +3. Name the type of lens which forms this kind of image [2] [2] [2] [2] [2] [2] [2] [2] [2] (e) A P (a) (b) (c) (d) (e) (a) (b) (c) (d) (e) (a) (b) (c) (a) B The figure shows a ray of white light P incident on an equilateral prism ABC . Name the surface on which dispersion takes place. What is the cause for dispersion? C Question 3 A body vibrating with forced vibration is acted upon by three forces, one is the restoring force, Name the other two forces. (i) Name the two kinds of mechanical waves. (ii) Sound wave in water is an example of which type of mechanical wave? Resistance of a heating element is high. (i) Name the material used as a heating filament. (ii) How does the resistance of the filament vary when the bulb is glowing compared to when it is not glowing? State Ohm s law. Give one example of a non-Ohmic resistor. The power rating of a fuse is 220V 100W. What are the two physical quantities which can be calculated from these values ? Question 4 An electric kettle draws a current of 4A for2.5 minutes. If the resistance of its element is 100 ohms, Calculate the electric energy drawn by kettle in kilojoules. (i) How are Natural isotopes different from Radio isotopes? (ii) Classify the following as Natural and Radio isotopes. 14C6, 235U 92. (i) What are back ground radiation? (ii) Give one example of an internal source of background radiations. (i) Which is the type of transformer which has turns ratio greater than 1. (ii) What is the principle of working of a transformer Draw a diagram to show the magnetic field due to a straight conductor carrying current. SECTION II Attempt any four questions from this section Question 5 A uniform metre rule is balanced at 45cm mark when a weight of 20gf is suspended at one end. (i) Draw a suitable diagram for the arrangement. (ii) Identify the clock wise moment. (iii) Calculate the weight of the metre scale. (i) Why is work done against friction said to be negative? (ii) Identify the class of lever whose mechanical advantage is always less than one. (iii) What is the function of the lever mentioned above? A block and tackle system has a velocity ratio of 4. (i) Draw a labeled diagram for the arrangement. (ii) If the block and tackle system has an efficiency of 80% calculate its mechanical advantage. (iii) Calculate the load it can lift when an effort of 100N is applied. (i) [2] Questions 6 Write an expression to calculate the amount of heat energy liberated by a hot [2] [2] [2] [2] [2] [2] [2] [2] [2] [2] [3] [3] [4] [3] substance to cool to 0 C. (ii) Two substances A and B have specific heat capacities 200Jkg-1K-1 and 1850Jkg-1K-1. Which of the two is a good conductor of heat. (iii) Why does wet soil take a longer time to get heated compared to dry soil? (b) (c) (a) 10 g of ice at -10 C is heated by a heater rated 220V and 250W when the ice melts and reaches a temperature of 90 C.Calculate the time for which the heater is used. { C of ice =2.1Jg-1K-1 , L of ice =336Jg-1, C of water= 4.2Jg-1K-1}. A convex lens is used as an erecting lens in a terrestrial telescope. Draw a three ray diagram to show the formation of the image. State the characteristics of the image formed. Question 7 The figure below shows a ray of red light and violet light incident with the same angle of incidence on a rectangular glass block. Red violet A (b) (c) (a) (b) (c) (a) (b) (c) [3] [4] [3] B C D Will the rays emerge parallel to each other from the face CD? (i) (ii) What is lateral displacement? (iii) Which of the two will show a greater lateral shift? (i) Name the phenomenon responsible for the sparkle in diamond. (ii) State the conditions for the above mentioned phenomenon to occur. (iii) The critical angle for diamond is 24 , what does this statement convey? (i) A type of electromagnetic rays is used in remote control of a television, Name it and state if it has a wavelength range greater or lesser than visible light. (ii) Why does the sun appear red during sunset? Question 8 A boys stands in front of a cliff and produces a two claps in one second, he hears the echo which coincides with his clapping and further he hears the echo only once after he stops clapping. Given speed of sound in air is 340ms-1. Calculate how far the boy is from the cliff. The stem of a vibrating tuning fork is placed in a trough containing water. (i) What do you observe in water? (ii) Name the phenomenon. (iii) Under what condition can it produce a loud sound? (i) State two difference between resonance and free vibrations. (ii) Why are stringed instrument provided with sound boxes? Question 9 (i) At what voltage and frequency is the power generated at the generating -station? (ii) Why is the voltage stepped up at the grid substation to 132kV? (i) An electric heater rated 220V and 8A is used for 2 hours everyday, Calculate the monthly bill if energy costs 4rupee 50 paise per unit. (ii) What is the commercial unit of electrical energy? (i) What are the factors affecting the magnitude of induced e.m.f. in a conducting coil? [3] [4] [3] [3] [4] [3] [3] [4] (ii) (a) (b) (c) Suggest two methods by which the speed of rotation of the D.C. motor can be Increased. Question 10 What are the safety precautions taken while a person handles radioactive element? (i) Radioactive decay and nuclear fission are nuclear phenomenon, How do they differ? (ii) Calculate the energy equivalent of 1 kg mass using E= mc2. With respect to an a.c. generator answer the following: (i) What is the principle of its working? (ii) What is the energy change? (iii) Name the law used to predict the direction of induced current in an a.c. generator. Veena Sriram HOD Physics Gitanjali Senior School Begumpet Hyderabad-500016 [3] [4]
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