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Class X Subject Physics (SCIENCE Paper 1) Time allowed: 2hrs Maximum Marks: 80 Attempt all the questions from Section I and 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) Which of the following physical quantities have same units? [2] (i) Force & Momentum (ii) Force & Torque (iii) Momentum & Energy (iv) Torque & Energy (b) A bullet is fired into an object and stopped. Which forms of energy is the mechanical energy (kinetic energy) of the bullet converted into? [2] (c) Mention the mechanical advantages of class I, class II and class III levers. [2] (d) Relate the SI unit and gravitational unit of force. [2] (e) Give one example of a no-work force with explanation. [2] Question 2 (a) Relate the horse power with the SI unit of power. [2] (b) A particle of mass 2 g is moving with uniform speed 20 m/sec along a straight line. Find its kinetic energy. [2] th (c) Light travels in a medium with a speed 3/4 times its speed in vacuum. Find the refractive index of the medium. [2] (d) Write down the conditions for total internal reflection. [2] (e) Draw a labelled diagram to show 90 deviation ( = 90 ) of a ray with the help of a right angled prism. [2] Question 3 (a) Determine the resistance of the conductor from the following current voltage (I V) graph? [2] V (Volt) 20 15 10 5 1 2 3 4 5 6 I (Amp) (b) The resistance of a cylindrical conducting wire of length L and cross sectional area A is R. Find the resistance of another conducting wire made of same material, length and cross sectional area each half of the other wire ? [2] (c) The latent heat of ice is 80 cal/g. Explain this statement. [2] (d) 2000 cal heat is required to raise the temperature of 1 kg substance of a material through 20 C. Find the specific heat of the material. [2] (e) Mention one difference between ray and ray. [2] Question 4 (a) What is forced vibration? Give one example. (b) Name the unit in which the sound level is generally expressed. (c) State the property used by bats to detect an obstacle. (d) Which of color in the visible spectra experience larger deviation? (e) Why are the household applications connected in parallel? [2] [2] [2] [2] [2] SECTION I (40 Marks) Attempt any four questions from this Section. Question 5 (a) A man of mass 60 kg runs up a flight of 30 steps in 15 second. If each step is 20 cm high, calculate the power developed by the man. Take g = 10 ms 2. [4] (b) Give the advantages of renewable source of energy with example. [3] (c) What is a pulley? What is the mechanical advantage of a single fixed pulley? [3] Question 6 (a) Draw a schematic diagram of a circuit consisting of a battery of four 2 volt cells a 5 ohm resistor, an 8 ohm resistor and a 12 ohm resistor , a plug key all connected in series. [3] (b) A house is fitted with a motor of 1 KW power, 5 bulbs consuming 0.2 A each and two fans of 80 W each. If all the appliances work for five hours daily, calculate the monthly bill. Energy cost Rs 5.00 per unit. The energy is supplied at 220 V. [3] (c) State two ways by which the strength of a magnetic field of an electromagnet can be increased. Why is soft iron generally used as the core of the electromagnet? State two advantages of an electromagnet over a permanent magnet. [4] Question 7 (a) Draw a ray diagram to illustrate the formation of an enlarged and upright image of an object by a lens. Name the lens used. Where the object should be placed relative to the lens? Will the image be real or virtual? [4] (b) A glass slab 2.5 cm thick is placed over a coin. If the refractive index of glass is 3/2, find the height through which coin is raised. [3] (c) Explain some important features of a musical sound. [3] Question 8 (a) Find the equivalent resistance between the points A and O in the following circuit. [3] (b) An observer stands at a distance of 850 m from the cliff and fires a gun. After what time gap will he hear the echo, if sound travels at a speed of 350 ms 1 in air? [3] (c) Two resistors of resistance 2 ohm and 3 ohm in parallel are connected to a cell of e.m.f. 1.5 V and internal resistance 0.3 ohm. Draw a labeled circuit diagram showing the above arrangement and the current drawn from the cell. [4] Question 9 (a) m1 g of steam, at 100 C is condensed to form water at 100 C. If there is no heat loss to the surroundings, the heat released in this process is used to convert m2 g of ice at 0 C into water at 0 C. Find : (i) the heat lost by steam in terms of m1. (ii) the heat gained by ice in terms of m2. (iii) Form a heat equation and find the ratio of m2 : m1 from it. (Specific latent heat of vaporization of steam = 2268 kJkg 1 ; Specific latent heat of fusion of ice = 336 kJkg 1 ; Specific heat capacity of water = 4200 Jkg 1 C1). [4] (b) Explain why steam pipes warm a building more effectively than hot water pipes in cold countries. [3] (c) Draw the representative diagram of a transformer and mention one application of a step up transformer. [3] Question 10 (a) State the precaution that must be taken while handling a radioactive source. (b) Why are materials of low work function preferred as thermionic cathode materials? (c) A nucleus 235X92 emits and a radiation. The final nucleus is bYa. Find a and b. [4] [3] [3]
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