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Bombay Scottish School, Mahim PRELIMINARY ASSESSMENT PHYSICS (SCIENCE PAPER 1) Grade : 10 Max. Marks : 80 Date : 18.01.2023 No. of questions : 09 Duration : Two hours No. if printed sides : 13 ______________________________________________________________________________ Answers to this Paper must be written in the paper provided separately. You will not be allowed to write during 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 A is compulsory. Attempt any four questions from Section B. The intended marks for questions or parts of questions are given in brackets [ ] ___________________________________________________________________________ SECTION A (Attempt all questions from this Section.) Question 1 [15] Choose the correct answers to the questions from the given options: (i) In the figure shown below, three forces F1, F2 and F3 are seen acting on a body pivoted at P. If each force acts separately and moment of force is same in each case, then: (a) Force F1 has the max. value. (b) Force F2 has the max. value. (c) Force F3 has the max. value. (d) All forces have same value. 1 (ii) Which of the following diagrams show the correct use of prisms in the periscope? (a) (b) (c) (d) (A) (B) (C) (D) (iii) Choose the correct meaning of the statement: The efficiency of a machine is 60% . (a) In the given machine M.A. > V.R. (b) 60 % of the total energy supplied is obtained as useful energy. (c) 60 % of the total energy is lost in overcoming the force of friction. (d) The power output is more than the power input. (iv) Two sound waves (S1 and S2) produced from two different sources are of same amplitude and are having frequencies 256 Hz and 512 Hz respectively. Then, (a) S2 is louder than S1 (b) S1 is shriller than S2 (c) S1 is called infrasonic and S2 is called ultrasonic. (d) S2 is shriller than S1 (v) In temperature v/s time graph shown below which of the substances P, Q or R has the lowest specific heat capacity? (a) (b) (c) (d) P Q R Cannot say since mass is not given. 2 (vi) Study the circuit diagram. How many bulbs will light up when switch A is opened and switch B is closed? (a) (b) (c) (d) (vii) The diagram shows a ball placed on a compressed spring flies away when the spring is released. Observe the diagram and state the energy change in the ball: (a) (b) (c) (d) (viii) How (a) (b) (c) (d) (ix) All 4 bulbs 3 bulbs 1 bulb 2 bulbs Kinetic energy to potential energy. Chemical energy to kinetic energy. Elastic potential energy to chemical energy. Elastic potential energy to gravitational potential energy. does a blind person recognize another person talking to him? by unique waveform of voice of an individual. by unique loudness of an individual. by unique amplitude of sound of an individual. by unique pitch of sound of an individual. The oxygen bubbles rising in the fish tank appear silvery when viewed at a particular angle. Choose the correct statement for the above observation: (a) light ray suffers total internal reflection while entering the bubble. (b) light ray refracts while entering the bubble. (c) light ray disperses while entering the bubble. (d) it happens because the bubble is transparent. 3 (x) In the following picture on Fleming s left hand rule of current carrying conductor, state what does the direction 1 and 2 indicate: (a) (b) (c) (d) 1 1 1 1 electric current, 2 force force, 2 electric current force, 2 magnetic field electric current, 2 - magnetic field (xi) A radioactive nucleus (X) decays with the emission of an alpha ( ) particle as shown in the equation below. + Choose the correct equation from the options given below: (a) a = c (b) b = d + 1 (c) a = c + 4 (d) d = b + 1 (xii) A heater has a rating 5000 W, 240 V; the electrical energy consumed in 60 min (in kWh) when connected to 240 V supply is (a) 5000 kWh (b) 60 kWh (c) 5 kWh (d) 30 kWh (xiii) Which of the following is the use of household electric meter? (a) to record the consumption of current by the lights, fans, TV etc. (b) to record the consumption of voltage used (c) to record the consumption of energy used (d) to melt the fuse in case of a short circuit. 4 (xiv) In the given figure, which of the following will happen if the magnet is brought closer to the solenoid? (a) (b) (c) (d) (xv) the the the the galvanometer galvanometer galvanometer galvanometer will will will will get deflected towards right get deflected towards left fluctuate with equal frequency remain as it is. Consider the following figure of a 3 pin-plug and choose the correct combination? (a) (b) (c) (d) 1 1 1 1 - Earthing pin, 2 - Neutral pin, 3 - Live pin - Live pin, 2 - Earthing pin, 3 - Neutral pin - Earthing pin, 2 or 3 Live or Neutral pin doesn t matter Earthing pin, 2 Live pin, 3 Neutral pin Question 2 (i) (a) Calculate the power of the motor of an elevator in kW, which can carry 10 persons of average mass 60 kg through a vertical height 20 m in 30 s. (Take g = 10N/kg). [3] (b) State the energy conversion in the following: EVs (Electric Vehicles) (ii) A car of mass 120 kg is moving at a speed 5 ms-1. It accelerates and attains a speed of 20 ms-1. Calculate the work done by the engine on the car assuming there is no loss of energy. [2] 5 (iii) The diagram given below shows two parallel forces acting on rod AB. Calculate the total moment acting on the rod AB in S.I. unit. [2] (iv) Redraw the diagram given below and complete the path of the ray AB till it emerges out of the rectangular glass block PQRS. In your diagram mark i, e, r and lateral displacement (L). [2] (v) Name the type of waves which are used for sound navigation and ranging. Why are these waves not audible to us? [2] (vi) A mixture of radioactive substances gives off three radiations. [2] (a) Name the radiation which is deviated most in magnetic field. (b) Name the radiation that will become an inert gas on accepting two electrons. (vii) The figure shows two coils P and S kept near each other. The coil P is joined to a coil, key and rheostat while the coil S is joined to a centre-zero galvanometer. A deflection is observed in the galvanometer once when the key K is turned on, keeping the rheostat at fixed position. Answer the following questions: [2] (a) (b) Name the phenomenon happening here due to which there is deflection in the galvanometer. Why is the deflection seen only once? 6 Question 3 (i) A lens is used to focus the radiations obtained from the Sun to burn a piece of paper. [2] (a) State the type of lens used. (b) State the type of radiations responsible for burning of paper. (ii) (a) What does in the V-I graph for non-ohmic conductor represent? (b) Two copper wires are of the same length, but one is thicker than the other. Which wire will have more specific resistance? [2] (iii) Figure below shows two identical tuning forks A and B of the same frequency on two separate sound boxes such that their open ends face each other. It is observed that when one of the tuning fork(A) is struck on the rubber pad and starts vibrating the tuning fork B also starts vibrating vigorously (with larger amplitude). State two reasons responsible for this observation. [2] (iv) Observe the figure shown below and answer the questions that follow: [2] (a) (b) Identify the process shown in the figure. State where will end A of wire shown in the figure be connected to? 7 (v) 50 g of metal piece at 270C requires 2400 J of heat energy so as to attain a temperature of 3270C. Calculate the specific heat capacity of the metal. [2] SECTION B (Attempt any four questions.) Question 4 (i) In the figure white light was allowed to pass through a triangular prism ABC. Study the figure the answer the questions that follow: [3] (a) (b) (c) Name the phenomenon occurring at the surface AB of the prism ABC. Define the phenomenon occurring at surface AC of the prism ABC. Explain the cause of the phenomenon mentioned by you in (a). (ii) Draw a ray diagram to show how a lens is used to obtain a real and enlarged image on a screen placed at a large distance on the other side of the lens. [3] (iii) (a) Copy and complete the diagram by drawing the respective refracted rays for violet and red colour. It is given that rays of both colours are parallel. [4] (b) Refractive index of water is 4/3. Calculate the speed of light in water. Speed of light in vacuum is 3 x 108 ms-1. 8 Question 5 (i) A boy uses a single fixed pulley to lift a load of 50 kgf to some height. Another boy uses a single movable pulley to lift the same load to the same height. [3] (a) Compare the efforts applied by them. (b) What will be the advantage of using a single movable pulley. (c) Which one will be preferred to raise the load and why? (ii) The diagram below shows a uniform metal scale balanced at 10 units mark by suspending a 120 gf at one end. Calculate the weight of the scale. [3] (iii) (a) A crane A lifts a heavy load in 5 seconds, whereas another crane B does the same work in 2 seconds. Compare the power of crane A to that of crane B . (b) A simple pendulum, while oscillating, rises to a maximum vertical height of 20cm from its rest position. If mass of the bob of the simple pendulum is 250g, find the velocity of the bob at its mean position given the pendulum is oscillating in friction less medium. (Take g = 10N/kg). (c) In the figure given below showing the changes in energy in an oscillating simple pendulum, identify the curve representing kinetic energy. [4] 9 Question 6 (i) The diagram (not drawn to scale) below shows the graphical relation between angle of deviation and angle of incidence, when light passes through a triangular prism of certain glass material. [3] (a) Find the angle of prism (A). (b) State the value of angle of minimum deviation. (ii) A monochromatic point source of light S is viewed by an observer O through a prism P. Complete the diagram by drawing two rays starting from the source S to show the image formed by the prism as seen by observer O. Label the image by letter I. [3] (iii) (a) Define refractive index. State how will increase in temperature of a medium affect its refractive index. [4] (b) State the change in speed and frequency of light ray when it moves from rarer medium to a denser medium. 10 Question 7 (i) The figure below shows a wire stretched over a sonometer. Stem of a vibrating tuning fork is touched to the wooden box of the sonometer. In the figure A the paper rider flies off. [3] (a) Name the phenomenon when the paper rider flies off. (b) The same vibrating tuning fork is touched to the wooden box of sonometer in figure B with the same length of vibrating wire. What will you observe in figure B and why? (ii) (a) A naturally occurring liquid X is used as a coolant in car radiators. Name the liquid X. Will the liquid mentioned by you have a higher value of specific heat capacity or a lower value? (b) Heat supplied to a solid changes it into a liquid. What is the energy absorbed during the phase change called? [3] (iii) (a) A cop is at a distance 120 m from a wall. A thief is 40 m from the cop. Cop fires at the thief and misses. The thief hears the sound twice with an interval of 0.5 seconds. Calculate the velocity of sound in air. [4] 11 (b) In the figure below, five pendulums can be seen. If pendulum D is made to oscillate, state which pendulum will oscillate with max. amplitude and why? Question 8 (i) In the device shown below: [3] (a) Identify wire A. (b) Identify wire B. (c) State the factor on which the thickness of wire A depends? (ii) A calorimeter of thermal capacity 63 J/K contains 200 g of water present at 700C. What mass of ice added will bring down the temperature of mixture to 200C? [Sp. Heat capacity of water = 4200 Jkg-1K-1. [3] -1 Sp. Latent heat of ice = 336000 J kg .] 12 (iii) The diagram below shows a circuit with the key k. Calculate: [4] (a) the resistance of the entire circuit when the key k is open. (b) the current drawn from the cell when the key k is open. (c) the resistance of the entire circuit when the key k is closed. (b) the current drawn from the cell when the key k is closed. Question 9 (i) A certain nucleus A (mass number 238 and atomic number 92) is radioactive and becomes a nucleus B (mass number 238 and atomic number 93) by the emission of a particle. [3] (a) Name the particle emitted. (b) State the change in form of a reaction. (c) State the reason for emission of gamma radiation. (ii) (a) A nucleus 202 84 of an element emits an -particle followed by a - particle. The final nucleus is . Find the values of a and b. (b) State one safety precaution in the disposal of nuclear waste. (iii) [3] (a) The figure shows a spiral coil wound on a hollow cardboard tube AB. Current is switched on by closing the key. Copy the diagram and mark the following: [4] 1. Direction of current in the coil. 2. Direction of magnetic field lines inside and outside the tube. 3. Polarity at the faces A and B. (b) It becomes more difficult to move a magnet towards a coil when the number of turns in the coil has been increased.Explain. ______________________________________________________________________________ 13
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