19/06/2014
Phy Obj 1-10. ADCDEEAEDE
11-20. EDABDDABCD
21-30 EECCECBDAA
31-40 AABAACCBBD
41-50 CDBCEDACBD
51-60 CCCBDDDDCE
1a) Satellite an artificial body placed in orbit round the earth or another planet in order to collect information or for communication. 1b) Cosmic (ii) Magnetic field 1c) The artificial satellite is first launched to space which produces visual signals to Tv stations and it's further transmitted or relayed to individual house and hence, the 2014 Brazil world cup be viewed. 2a)Do graph Ur Sef 2b) D = √(x2 - x1)^2 + (y2 - y1)^2 = √(-3-5)^2 + (-4-(-2))^2. = √64+36 = 10unit 3a) Yes fractional force depend on the nature of the surface 3b) Walking without fractional force depending on the nature of the surface, there would be slipping and skidding 4a) The work done is the area of the rectangle * Area of rectangle = L x B Work done (I) 2F^1 x d^1 = 2F^1d^1 ( ^ means raise to power) Work done (ii) F^1 x d^1 = F^1d^1 Difference in work done = 2F^1d^1 - F^1d^1 = F^1d^1Nm 4ii) Work done is defined as the minimum energy required for electrons to be liberated from the surface of a metal when light is incident onit b) E= hf but C= F/|, F = C//| , E= hc//| E= 5.5 x 10^-9J, /|= 6.6x10^-34 x 3x10^8/5.5 x 10^-9 /|=3.6x10^-17 {where J is joule, /| is lander } 5a) 85 - x/ 50 - x = 100 - 0/40 - 0 4(85 - x) = 500 - 10x -4x + 10x = 500 - 340 6x = 160 X= 26.67oc 6) V = 3x10m/s From the diagram, T=12s(time taken to complete one cycle) 6aii) V=F/|, F=1//| , /|= VT { where /| is lander } /|=3x10^3 x 12 = 3.6x10^4m 6aiii) F=1/t = 1/12= 0.083Hz 8a) E=2.0v, r=1ohm, R=?, V=1.92v From E= I(R+r) also, V=IR, I=V/R E= V/R(R+r) 2R= 1.92R + 1.92 2R - 1.92R = 1.92 0.08R = 1.92 R = 1.92/0.08 =24ohms 9a.) The basic unit of measure of electricity is known as the Watt. One thousand Watts are called a kilowatt. OR .the unit is kilowatt per hour (kwh)/ def 1kwh is the energy consumed by power consumption of 1kilowatt during 1hour. (9b)Two Advantages At high voltages (i)to ruduce the energy loss in long-distance transmission, (ii)also for greater efficiency during long distance transmissiön. two Advantages at Low Current (i)to accomodate the use of low using electrical appliances, (ii) to promote even distribution of current. 10a) Natural radioactivity is the spontaneous distingration of the nucleus of an atom during which alpha particle or beta particle,or gamma rays or a combination of any or all the three and heat (or energy) are released. While Artificial Radioactivity this is an ordinary material,not normally radioactivr is made radioactive by bombarbing it with radioactive particles. 10b) Two Uses Of Radioisotopes. i Radioisotopes are used in medicine as radiotherapy. ii. Radioisotopes are used in industry to study defects in metals and welded joints. iii. Radioisotopes are used in geological research for radio-dating 11a) Work function is defined as the minimum energy required for electrons to be liberated from the surface of a metal when light is incident on it 11b) E= hf but C= f/| , f=C / /| E= hc / /| , E= 5.5 x 10^-9 J /| = 6.6x10^-34 x 3x10^8 / 5.5 x 10^-9 = 3.6 x 10^-17m 13a )A vacuum flask, or thermos, does not allow heat transfer by any of the three ways that heat can travel. The silver coating on the inner bottle prevents heat transfer by radiation, and the vacuum between its double wall prevents heat moving by convection. The thinness of the glass walls stops heat entering or leaving the flask by conduction. The case surrounding the flask provides additional insulation. 13aii) Cork 13b) Inclined plane (ii) Wheel and axel 13bii) m=6000kg , h=0.25m , L=0.75m EFF=85% (I) * V.R of a screw jack = distance move by effort/load 30 x 2 x 3.142 x 0.75/0.25 =565.2 (ii) * M.A = Eff x VR/100 = 85 x 565.2/100 M.A = 480.42 = L/E Effort= L/480.42 = mg/480.42 = 6000 x 10/480.2 E= 124.9N 14a) Convex mirror or Converging mirror * It produce an erect image and has a wide range of view 14b) A piano have strings of different lenght so that it can produce different of sound 14bii) F = k/L .... Where F is frequency, L is length 14c)*choose two - Temperature - Humidity - frequency of sound in air - wavelength of sound in air 14cii) fo = 220Hz (open pipe) Ist overtone freq of open pipe = Ist overtone freq of closed 2fo cp = 3fo cp 2 x 220/3 = 146.67HZ ( fo cp) For Closed pipe V = 4fl , l=V/4f 330/4x146.67 = 0.56m For Opened pipe V = 2fl , l = V/2f 330/2x220 = 0.75m 17ai) 1.The absorber is usually a sheet of high-thermal-conductivity metal with tubes or ducts either integral or attached. Its surface is painted or coated to maximize radiant energy absorption and in some cases to minimize radiant emission. 2.The insulated box, provides structure and sealing and reduces heat loss from the back or sides of the collector. 17aii)Flat Plate Solar Collector is the key part of the flat plate solar water heater. It consists of absorber, cover glass, insulation, and shell. The metal absorbing plate with coating is welded on the red copper pipe. The cold water or the medium liquid is heated when running through the pipe. The transparent cover glass allows visible light to pass through and blocks the the far infrared. It means the sunlight can pass the cover glass and reaches the absorber to produce heat, but the far infrared resulted from the radiation of heated absorber is blocked and kept inside. In this way, the heat loss is reduced. And the heat-absorbing efficiency and the temperature of the absorber can be increased. There are usually three kinds of coatings: black selective coating, black chrome coating and blue tinox titanium coating. In areas with winter temperature above 0 ℃, system of direct-heating of cold water is applicable, but in areas with winter temperature below 0 ℃, the user could input medium liquid in the system to heat cold water indirectly as an alternative. * Material: A) Cover glass:transparent toughened glass B) Absorber core:copper and aluminum complex or all copper C) Pipe: red copper D) Shell/bracket: aluminum alloy / galvanized steel 17b).One of the main differences between a telescope and a microscope is that A telescope is used to view things that are far whereas a microscope is used to view things that are very near. -
