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THE BISHOP'S SCHOOL - CAMP SECOND PRELIMINARY EXAMINATION PHYSICS - 2017 IME I 2 HOURS MARKS : 80 I CLASS : X DATE : 17- lt - 2Ol7 NoTE : Answers to thi'i Daper must be written on the paper provided separately' You will not be allowed to write in the first 15 minutes. This time is to be spent in reading the question paper' The ttme given at th r head of this paper is the time allowed for writin9.thg answers' s ctbn A |5 comp'i'Joryittempt any four questions from Section B The intended marks for q restions or parts /Jf questlons are given in brackets Answer Att SECTION A questions from this section' 9-UESIIeNI 3. What should be the angle between the force and the displacement, (2 x s) in order to get : i) l,laximurrr work ii)lvlinimuffr work State the cnerqy changes in the following: {l) Gevser lil)Solar cell Two sph.rrical objects of mass in the ratio 1 : 2 are dropPed from the same height' (r) Srale the ratio between the. velocrL;es when lhey strlle the groLrnd (ii)The ratio of the forces acting on them during the moion. (i) On what factor does cenlre of gravity of an object depend? (li) Give an example of an object whose centre of gravity lies outside the booy' 100 N force at the iii fne iron gate of a building is 3 m broad. It can be opened by applying gate middle of the gate. Calculate the least force required to open the (ii) Where should the for.-e be applied? f ( b. c. (2xs) qUEEII.SLL a. :itate two facto.s on \ /hich the lateral displacement depenos. b. A ray of light passes l:hrough a right angled prism as shown in the given figure angle of incidence at lhe faces Ac and c. d. e. BC. State the A Complete the following sentences: (i) The pitch c'f sound increases if its frequency (ii)If the amplitude of a sound is doubled, its loudness becomes -.----' The wavelength of waves produced on a surface is 20 cm lf the wave velocity is 24 ms Calculate i (i) The nLrmber of waves produced in one second (ii)The time required to produce one wave. Name the prism requirecl to obtain the spectrum ol : (i) Ultrir violet light (ii)Inf' a fed light ' (2 x 5) u. Wnaiis tn" quantity of heat produced in a coil of resistance 80 Q if current of 3Aispassed thr ough it for 4 seconds. b. A cell is used to send current to an external circuit (r) How does the voltage across its terminal compare with its e m f? terminal voltage? iii;Unoer wfrat conditidns Is the e m f of a cell equal to its B for the following combination points and A the c. djlculate the equivalent r-esistance between + 'lr' of resislors. ouEsrrgl-l t5 A d. e. Define the term speciflc heat capaclty ano state its s.I. unit. a liquid from 25 !C to An ele..rlric heater of power 1000 W rarses the temperature of 5 Kg of 31oC rn 2 mtnutes Calculate : (i) Th,: heat capacrty (ii)Tl',e specific heat capacity of the liquid rrl L) (2xs) OUESTION 4 a. What is a calorimeter? Why is it made of copper? b. a radioadive source's'placed in a thick lead walled container. The radiations given out are allowed to pass through a magnetic fleld, (i) complete the dlagram to show the path of alpha, beta and gamma radiations. (rl)Why is the source kept in a thick walled lead container? Thar d;agram shows <_ LEAD BOX E Rr'ADro,4cTtv I ' icuRCE S c. d, e. Comolete the followino nuclear chdnoes: 2rsAq) ---..oc.-------j A ----2S---------" , C Define Nuclear fission and Nuclear fusion. Mention two safety rules for handling radioactive materials. SECTION B ouEsTroN a. 5 Angwer any FOUR questions from this sectign. (3+3+4) A, B and C are three forces of magnitude 8 N, acting in the plane of the paper as shown in the figu.e. Point O lies in the same plane. A \ --;-i \"'V" (i) Name the forces producing (a) Clockwise (b) Anticlockwise moments Which force has least moment about O? (iii) What is the resultant torque about point O? b. Name a machine which is used toi (i) 14ultiply force ( ii) Multiply speed (iii) Change the direction of force applied c. A vessel of negligible heat capacity contains 5.0 kg of water at 50 0c. If 5.0 kg of ice at 0 oC is added to it, find: (i) Heat energy imparted by water in fall of its temperature from 50 0C to 0 0C. (ii) l4ass of ice melted (iii) Final temperature of the mixture (iv) Mass of werter at 0 0C in the mixture (ii) ouEsrroN 6 ouEs'rroN 7 (3+3+4) a. The stem ot a vibrating tuning force is pressed against the table top. (i) Will it produce an audible sound? ( ii) Does it cause the table top to set in vibratlon? If Yes, what type of vibrations are they? (iii) Under what conditions does it lead to'resonance'? (i) A D.C. nrotor is rotating in an anticlockwise direction. How can the direction of rotation be reversed? (ii) State the main difference between a Step - up and Step - down transformer. (i;i)What is the function of a step - up transformer? b. An isotope of uraniurn has a mass number 235 and atomic number 92. (i) what ls the number of protons and neutrons in its nucleus? (ii) What is the number of electrons in the neutral atom of this isotope? (iii) Do all isotopes have the same number of neutrons? (iv) State one harrnful effect of radioactivity. a. (3+3+4) The diagram given alongside shows an object O and lts image I. Copy the diagram and draw ,juitable rays t.o locate the lens and its focus Name the lens used in this case. ?- 1,1 .-1 t*) I b. The given figlrre shows a weightless lever in equilibrium Neglect friction at the fulcrum F. (i) State the prlnciple ot moments as apolied to the above leve;: (ii)Calct late its mechanical ad\iantage (iii) Name the type of lever which has mechanical advantage greater Lhan one. c, The daagram below shows a temperature _ tlme graph for a substance P. AT, o" z ul F (i) What does part CD represent? A (ii)What is the melting point of the substance? (lli) What ls the boiling point of the substance? (iv) Why is the part BC shorter than part DE? ouEsrroN TlrwrE --> (3+3+4) 8 a. An electrlc heater is rated 220 V - 550 W (i) What does thls statement mean? (ii) What is lts safe current limit? (iii) consumed in 3 hours. 000 km /s. What ls its refractave Index? (veloclty of Calculate the electrical energy b. -fie velocity of llght in diamonJ is t2o light in air is 3 x 10 3 m/s) c, Give scientific reason for the followingi {i) Hot water bottles are used for fomentatlon' (ii) Drinks get cooled more quickly by adding pieces of ice at 0 oc than ice cold water at 0 OUESTION 9 a. (i)How is the volume of water affected when it is boiled at 100 oC? (ii)How is the boiling point of water affected when some salt is added to it? (iii)What is effect of increase in pressure on the boiling point of water? h. Study_the given di_agl'?!n. oC. (3+3+4) (i) state r,he polarities developed at the ends A dnd B (ii1 suggest two ways of increasing the strength of the electrcmagnet so formed' r:. Two re.iistors are joined with a battery such that: (l) Satne current flows through each rcsistor' (li) Potentlal difference is the same across each reslstor' (ili) Equivalent resistance is less than either of the two resistors' (iv) t-:quivalent resistance is more than either of the two reslstors' (3+3+4) SugsrrrgN_lq a. pulley system with a veloclty ratio of 4 ls used to lift a load of 150 kgf through a vertical A calculate treignt Lf io m. The effort required is 50 kgf in the downward dlrection (l) The distance moved by the effort (ii) work done bY the effort (iii) Mechanical advantage l.1 te\ : b. The dia,gram shows three rays A, B and C starting from the source'P' uD to the water surface. (criticerl angle for water air surface is 48 o). - 4rR WATER (i) Copy and complete the path of the three rays (ii) Name the phenomenon exhibited by rays A, B and c. ^0C is poured into it' 'n bucket con[ains 8 kg gf water at 25 oC. 2 kg of hot water at 80 c. - frf"gt""ting the heat e;ergy absgrbed by the bucket, calculate the final temperature of water. t, L'1 I )
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