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MOUNT CARMEL SCHOOL BAIJNATH PRE-BOARD EXAMINATION(2021-2022) CLASS-X PHYSICS TIME:1.5Hrs SECTION-A(ALL QUESTIONS ARE COMPULSORY) Question:1 Choose the correct answer from the given option : 1) Which one has more heat energy at 0o Celsius-1g ice or 1 g water? a) 1 g ice b) 1 g water c) Both have same heat energy d) 1 g ice has no heat enegy, 1 g water has 80 calorie heat energy. M.M.40 (10*1=10) 2) Which characteristic of sound distinguishes different sound having same pitch and quality? a) Intensity b) Loudness c) Frequency d) Amplitude 3) Radioactive sources emit three types of radiations. Which radiation has zero mass? a) Alpha radiation b) Beta radiation c) Gamma radiation d) All of these 4) Amount of heat energy required to melt 5 kg of ice at 00 celsius is (specific latent heat of ice=336J g-1 a) 1680000 J b) 1680 J c) 168*103 d) 168 KJ 5) Current is flowing in a circular loop.which of the following statement is incorrect? a) Looking at the face of the loop if the current flows in anti clockwise direction then that face has south polarity.If the current flows in the clockwise direction then that face has north polarity. b) Near the centre of the loop the magnetic field lines are nearly parallel. c) Magnetic field lines become denser if the current in the loop is increased. d) At the centre the magnetic field lines are along the axis of the loop and normal to the plane of the loop. 6) Which of the following electromagnets will be a stronger one a) b) c) d) Electromagnet of figure-I Electromagnet of figure-II Both will have the same strength None of the above 7) If the length of string is half,what happens to the frequency? a) Decreases b) No change c) Increases d) None of the above 8) In series combination of resistors a) Total resistance is reduced b) Total resistance is increased c) Same current flows through each resistor d) Both (B) and (C) 9) When a cell is in use a) Its terminal voltage is equal to the electromotive force b) Its terminal voltage is greater than the electromotive force c) Its terminal voltage is less than the electromotive force d) The relation between its terminal voltage and electromotive force depends on its internal resistance 10) Two domestic electric circuits are shown below. Three lamps each of 100W are used in each circuit. Which of the circuit is correct? a) Circuit-I b) Circuit-II c) Both d) None SECTION-B (ATTEMPT ANY THREE QUESTIONS) Question-2 1) a) State two ways by which the frequency of transverse vibrations of a stretched string can be increased. b) Why does the amplitude of a vibrating body continuously decrease during damped vibrations? (3) 2) An electrical appliance is used at 1000kVA, 220V.If the appliance is operated for two hours calculate the energy consumed by the appliance in (1) kWH (2) joule (3) 3) Following diagram shows three different mode of vibrations P, Q and R of the same string. (4) i) Which vibration will produce a louder sound and why? ii) The sound of which string will have maximum shrillness? iii) State the ratio of wavelength of P and R. Question: 3 1) The V-I graph for a series combination and for a parallel combination of two resistor is shown in the figure below. Which of the two A or B represents the parallel combination? Give a reason for your answer (3) 2)a) b) A certain amount of heat Q will warm 1 g of material X by 30C and 1 g of material Y by 40C.Which Material has a higher specific heat capapcity? State the law on which principle of mixtures is based. (3) 3)i) The diagram (a) and (b) given below are of a plug and a socket with arrow marked as 1 ,2,3 and 4,5,6 respectively on them.Identify and write live(L),neutral(N) and the earth(E) against the correct number. ii) Calculate the electrical energy consumed when a bulb of 40 w is used for 12.5 h every day for 30 days (4) Question: 4 1) A nucleus 11Na24 emits a beta particle to change into magnesium (Mg). a) Write the symbolic equation of the process. b) What are numbers 24 and 11 called? c) What is the general name 12Mg24 with respect to 11Na24? (3) 2) The figure given alongside shows an electromagnet. i) What will be the polarity at the end X? ii) Suggest a way by which the strength of the electromagnet referred to in the question,may be increased. (3) 3) A piece of ice is heated at a constant rate. The variation of temperature with the heat input is shown in the graph below: i) ii) What are represented by AB and CD? What conclusion can you draw regarding the nature of ice from the above graph? (4) Question: 5 1) Calculate the equivalent resistance between P and Q from the following diagram. (3) 2) i) ii) 3) Which of the two wires of similar dimensions, copper or nichrome, would you use for the electric heater element ?Give reasons to justify your answer. Two fuse wires of the same length are rated 5A and 20A.Which of the two fuse wires is thicker and why? (3) 0 0 A hot solid of mass 60 g at 100 C is placed in 150 g of water at 20 C.The final steady temperature recorded is 250 C. Calculate the specific heat capacity of the solid. (4) Question: 6(A) 1) When does the nucleus of an atom become radioactive? (3) 2) How is the radioactivity of an element affected when it undergoes a chemical change to form a chemical compound? 3) What are background radiations? (B) 1) 2) 3) Write one advantage of connecting electrical appliances in parallel combination. What characteristics should a fuse wire have? Which wire in a power circuit is connected to the metallic body of the appliance? (3) (C) Two pendulums C and D are suspended from a wire as shown in figure below.Pendulum C is made to oscillate by displacing it from its mean position.It is seen that D also starts oscillating. 1) 2) 3) 4) Name the type of oscillation, C will execute. Name the type of oscillation, D will execute. If the length of D is made equal to C,then what difference will you notice in the oscillations of D. What is the name of the phenomenon when the length of D is made equal to C. (4)
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