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IUai Sri Gurlev|| GRADE BGS WORLD SCHOOL 2023-2024 Pre-Board Exan PHYSICS SCIENCE PAPER-I Maxium marks :80 Tine Allowed: Tvo hours Answers to this paper must be written on the answer sheet provided separately. You will not be allowed to write during the first 15 minutes. This time is to be spent in reading the Ouestion paper. The time given at the head of the paper is the time allowed for writing the answers. Section Ais compulsory and Attempt any four questions from Section B. The intended marks for questions or parts of questions are given in the brackets /1. SECTION A (40 Marks) (Attempt all the questions from this section) Question I options Choose the correct answer to the questions from the given () |15] of lms. Another A body of mass 20kg is moving with a velocity the body B of mass I kg is moving with a velocity of 20ms'. Find ratio of kinetic energy of Aand B. a. 1: 10 (ii) IHorse Power (HP) = a. 446 (iii b. 1:20 b.766 c.1:30 d. I:40 Watt. c. 746 d. 674 a speed of An aeroplanc is flying at an altitude of 10,000 m at 300 kmph. The aeroplane at tlhis height has: Page 1 of 9 Wai Sri Gurude a. only GRADE % kinelic encrgy b. only potential encrgy C. kinetic and potential energy d. zero kinetic and potential energy (iv) When a Mash light is switched on the electric cnergy a. directly changes to light energy b. irst changes to light energy and then to heat energy c. first changes to heat energy and then to light energy d. None of the (V) above. In a uniform circular motion: a. specd of the body continuously changes because the direction ol motion changes. b. velocity of the body continuously changes because the direction of motion changes. c. the motion of the bodv is acceleraled d. both (i) and (ii) (vi) 1 ball of mass m is dropped from a height 'h. a. Potential energy of the ball at the ground level is mgh b. Potential energy of the ball at the height h is mgh c. kinetic energy of the all at the ground is zero d. both (i) and (iii) (vii) In case of a simple microscope the object is a. at F b, betwcen F andC c.at 2F dat infinity (viii) An object is placed in front of a diverging lens. The image produced by the lens is: a. Real, inverted, magnified. c. Virtual, erect, (ix) magnificd b. Virtual, erect, dReal, diminished inverted, diminished The least resistance that can be obtained by combining 22,49, 1Q and 10022 resistors is . 2Q b. 192 c. <10 d. >0 Pa2 of9 GRADE X (Uai Sri CGurudevl| replaced by a In the given arrangement, the three resistors are to be resistor? single resistor, Vhat will be the value of that (x) (a) 492 (b) 62 (c) 992 (d) 1892 is halved, the heat When the current Ilowing through a resistance (xi) produced in it will be (d) four times (c) double medium which of the (xM) Vhen lpht travels from a denser to a rarer (a) One-fourth (b) Onc-half following will change? (a) wavcength and velocity (b)frequency and wavelength (c)frequency and velocity (d) wavelength, frequency and velocity (xiii) During short circuit, the current in the circuit (a) decreases considerably (b) incrcases heavily (c) does not change (d)keeps on incrcasing and decrcasing continuously two (xiv) The characteristic of sound which enables to differentiate between sounds of different intensity is: (d) Loudness (c) Pitch (b) Amplitude (a) Quality is (xv) Vibrations produced in a body under the influence of a periodic force (a)forced vibrations (b) resonant vibrations (c) damped vibrations (d) sympathetic vibrations Question 2 (i A pieceofstone ticd at the end ofa thread is whirled in a horizontal circle with uniform speed by hand. (a) What will be the direction of the acceleration of the stone at any instant? (b) Nanc the force and its direction which acts on the hand. State two diflerences between Centripetal force and Centritugal force. Page 3 of 9 (2 GRADE X JjJai Sri Gurudes|| (m) Under what condition will a body undergo (a) translational motion (b) rotational motion [21 (iv) A, Band Care three forces cach of magnitude SN acting in the plane (2] of the papcr as shown in the diagram. Point O lies in the same plane. (a)Name the forces producing (i)Anticlockwise moments (ii) Clockwise moments.(b)Which force has the ercatest moment about 0. Give reasons. B 0.Sm .9:9m.. (v) A canon ball of mass 500 g is fired with a speed of 1Sms, Find a. Its kinetic enerey and b, Its [2] momentum Question 3 () State the principle of reversibility of light with the help of a ray [3] diagram. (ii) A lens forms an erect, magnificd and virtual image of an object (a) Name the kind of lens, [3) (b) Draw a ray diagram to show the formation of image (c) Name a device which uses this principle (iii) Give reasons for the following: During the day: (a) Clouds appear white. (b) Sky appears blue (iv) Observe the given circuit diagram and answer the questions that follow: (a) Calculate the resistance of the circuit when the key K completes the circuit. (b) Calculate the current through 392 resistance when the circuit is complete. Pape 4 pf 9 [2 (3) GNADE (v) (a)When a tuming fork |vibatngl is held close to cat, one icars a |4 faunt hunn, The sane vabrating tunug lok] is held suclh that at stem is in contact witlh the table sutface, tlicn one hears a loud sound. Explain. (b)A nan standing in front of a vertical clilf fies a un. Ile hears the ceho afler 3.5 seconds, On noving closer to the cliff by SAm, he hcars thc echo aller I seconds.(Calculate the dstance of the clilf from thc inital position of tlac mm SECTION- B (40 Marks) (Atempt any four quesins om this sectian) Question 4 Infrared radiations are used for signals during war. Give reason Which one of tle following rapis A or B shows free vilrations in vacuum and which one shows free vihrations in a nediun? (b) How did you come to this coclusion. (iii) Caleulate the cnergy in kWh Consumd in a nuntlh, in a house Page 5 ot 9 Jai Sri Gurudev GRADE X using 2 bulbs of I00W cach and 2 fans of 60W each, if the bulbs and the fans are used for an average of 10 hours cach day. (iv) (a) What are (2] superconductors? (b)State one difference between normal reflection and total intermal reflection Is it possible to burm a picce of paper using a lens in day light. Draw a ray diagram to support your answer. (21 Ouestion 5 (a) Obseve the diagram given below and state whether the bulb [3) will glow or not when we switch on K Butb Fro1 A.c tains 230 V K (b) Is it safe to handle the bulb when the switch is OFF? (c) Giveareason for your answer in (b) (1) Write two properties common to all the electromagnetic radiations. (21 (iii) The refractive index of water is L.33 at a certain temperature [2] When the temperature of water is increased by 40 C,the refractive (iv) index changes to 'x'. State whether x <I.33 or x > 1.33. Why? Alens of focal length 20 cm forms an inverted image at a distance (3) 60 cm from the lens. (a) ldentify the lens. (b) How far is the lens present in front of the object? (c)Calculate the magnification of the image Question 6 (i) (a) Name the electrical appliance shown in the diagram below [21 (b) Name the material of the wire used in this device. Page 6 of9 () Aby stacing in front of wall ta dstace of tSm peouces 2 clups pet seoed lie sices that he s of hes cagpig ncites with the t The cha is heand only cocE whe cdagpity is stpprt. Caloulate the speud of srnd (in) The WEve lengths for the lsght of red and bluc colours atc ncariy 7#1 m and 4z1m tespectivcly (a, Whach colour has the atet spod in a vacam (bjWhch coivr has 2 gcater specd (w) Thc Giayratn belaw shws ap t surce itsade a atet coitaier Four rays A, B, C, D starting from the sourceP are shran up to the water surface aCopy the diayram and show the path of thesc rays after strikng the water surface. The Critical Angle for water air surface is 4k WATER (b) Name the phenomenon which the rays B and D exhibit. 7cf GRADE X ILai Sri Gurudes| Question 7 (i)A boy tunes radio channel ina radio station 93,5MIlz. Name and (21 define the scientific phenomenon involved in tuning the radio channel. (21 (i) (a)What is the mcaning of the statement "The power rating of an appliancc is 60W, 220V (b)State the function of main switch in an clectric circuit. |2] (ii) How does a trawier man eatch fish in deep water? [21 (iv) Draw a displacement, distance graph for two waves A and B such that the amplitude of wave A is three times that of wave B. (v)Draw a ray diagram to illustrate how a ray of light incident obliquely [2] on one face of arectangular slab of uniform thickness emergecs. Question 8 [2 (i) State whether the following statements are true or false. (a) The position of the centre of gravity of a body changes when the body is deformed. (b) The centre of gravity of a frely suspended body always lies vertically above the point of suspension, (i) Differentiate between Unifom linear motion and uniform circular motion. Your answer should be with respect to speed, velocity and acceleration only. (ii) When a force acts on a body, under what conditions will the 21 [2] work done be zero? (iv) Why is it that we say negative work is done when a cricket [2) fielder takes a catch? (v) IfF is the force, S is the displacement, Wis the work done and [2] Ois the angle between the force and displacement, Calculate the work done if: (a) 0 =09 (b) = I80 Pagc 8 t 9 ILai Sri Gurudes GRADE X Ouestion 9 (i) Fill in the blanks: (a) J: Calorie (b) I kWh: (2] (i) Calculate the work done When a car of mass 500 Kg changes its speed from IS kmph to 45 kmph. (2) (ii) State Work Energy Thcorem. Give the formula to calculate the work done when a force is applied on a moving body [2 according to Work Energy Theorem. (iv) Consider a body falling from a height. If m is the mass of a (2) body, v is the final velocity, h is the height and g the acceleration due to gravity, then: (a) The PE at the height h is given by: (b) The KE just before the body hits the ground is: (c) The PE just before hitting the ground is: (c) The KE at the height h is : (v) Give the energy changes in the following: [2 (a) Photosynthesis in green leaves (b) Respiration (c) Microphone (d) Ceiling fan Page 9 nf 9
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