Formatting page ...
DE ELHI PUB BLIC SCH HOOL NEW WTOWN KOLKA ATA SE ESSION 20 013-2014 SELECT TION EX XAMINAT TION CLASS S : X-SET A SUBJE ECT : PHY YSICS FULL MA F ARKS : 80 T TIME : 2H HOURS An nswers to th his Question Paper must t be written on the paper provided separately. s Yo ou will not be e allowed to o write durin ng the first 15 1 minutes. This time is s to be spent in reading the t Question n Paper. The e time given n at the head d of this Pap per is the tim me allowed for fo writing th he answers. Section n A is compu ulsory. Attem mpt any four r questions from f Section n B. T intended The d marks for questions or r parts of qu uestions are given in bra ackets [ ]. estion paper r consists of f 4 printed pa ages. This que SECT TION A (4 40 Marks) Atte empt allquestions from this section n Question n1 (a) Write W two co onditions for hearing a distinct ech ho. (b) A woman dr raws water from f a well using a fixe ed pulley. The mass of the t bucket and a w water togeth her is 6.0kg. The force applied a by the t woman is i 70N. Calc culate the 2 m mechanical advantage. a ( (g=10m/s ) (c) For F the same e kinetic ene ergy of a bo ody, what sh hould be the e change in its velocity if its m mass become es four time es? (d) Give G the dire ections of in nduced curr rent in th he following g figures. Mention two o characteristics of a go ood (e) M em mitter. 2+2+2+2+2= =10] [2 Question 2 (a) X does 500J of work in h and Y do oes 600J of work w in h. What will be b the ratio of th he power de elivered by X and Y . (b) Name N the pr rinciple whic ch the optic cal fibre is based b on. Why W is that principle p use ed? (c) If f the amplit tude of a wa ave is tripled d, what will l be effect on n its loudness? Give re easons. (d) Distinguish D between b step p-up and step-down tra ansformer. (e) State two pre ecautions th hat must be taken while e handling a radioactiv ve source. [2 2+2+2+2+2= =10] n3 Question (a) Mention M any y two charac cteristics of f non-contac ct forces. 1 (b) State two properties of alpha radiation. (c) In the given diagram given below find the ratio of i1 and i2. (d) Why do we prefer a magnifying glass of smaller focal length? (e) The momentum-time graph of a particle moving along a straight line is shown in the figure. In which part of the graph, a constant force acts on the particle? Give reasons. A B C [2+2+2+2+2=10] time Question 4 (a) 0.4kg of water at 100 is mixed with 0.2kg of water at 10 and stirred well. Neglecting the heat absorbed by the container, calculate the final temperature of the mixture. (b) State two uses of cathode ray tube. (c) Ultraviolet bulbs have quartz envelopes instead of glass. A (d) V-I graph for two conductors A and B is shown in the B given figure: Do A and B follow Ohm s law? If not why? (e) Distinguish between specific heat capacity and heat V capacity. [2+2+2+2+2=10] I SECTION B (40 Marks) Attempt any four questions from this section Question 5 (a) In the given diagram a uniform half metre scale PQ is balanced horizontally across a knife edge. Calculate (i) the mass of the scale, (ii) the force on the knife-edge, (iii) state the direction in which the force on the knife-edge, acts. (b) Why is it easier to open a door by applying the force at the free end of it? (c) Mention three disadvantages of solar panel. [4+3+3=10] 2 Question 6 (a) Copy the diagram in your answer book. I and I1 are two images; one only due to lens(in the absence of glass slab) and other due to refraction through lens and glass slab. Complete the ray diagram and identify which image is due to refraction through the lens only and which is due to refraction through the lens and glass slab. (b) Find by construction the position of a lens and its main foci on the optic axis OO if S and S are respectively, the object and image points. (c) State three factors affecting the refractive index of a medium. [4+3+4=10] Question 7 (a) The wavelength of a sound wave is 66m. Calculate the frequency of the wave, if the velocity of sound in air is 330m/s.Would this sound be audible to the human ear? (b) When a vehicle is in motion, sometime a rattling sound is heard. (i) Why does this happen? (ii) Name the phenomenon taking place. (iii)Suggest a way by which the rattling sound could be stopped. (c) Distinguish between renewable and non-renewable sources of energy.(three points) . [3+4+3=10] Question 8 (a) In the given diagram, calculate the reading of A when i. K is closed ii. K is open. (b) Mention any two energy losses of a transformer. What should be done to minimize these losses? 3 (c) A current carrying wire is held between the poles of a magnet as shown in the figure. State the direction of force experienced by the wire. State the law you have used. [4+3+3=10] Question 9 (a) How does the position of an element change in the periodic table when it gives out (i)an -particle (ii) a -particle? (iii) ray. (b) Compare the deflection of electron beam caused by electric field and magnetic field of same length. (3 points) (c) Mention how two factors affect the magnitude of induced current. (d) In a cathode ray tube, oxide coated filament is preferred over a tungsten filament. Why? [3+3+2+2=10] Question 10 (a) Two solid bodies each of mass m are heated at a uniform rate under identical conditions. Their change in temperature is reflected graphically in figure. (i) What are the melting points of solid I and II? (ii) What is the ratio of latent heats of solid I and II? (iii) What is the ratio of specific heat capacities of solid I and solid II? (b) 0.5kg of water at 30 is kept in refrigerator which can remove heat at an average rate of 30J/s.How long will it take to cool the water to 5 ? Specific heat capacity of water=4200j/kgK (c) (i) It is generally colder after hailstorm than during or before the hailstorm. Explain. (ii) State two ways to minimise global warming. [3+3+4=10] 4
|
