NECO PHYSICS ANSWERS ================================== Physics OBJ: 1-10: BAEDEECDEB 11-20: CDADDDBCBB 21-30: DBEBBEADEB 31-40: ABEBCBCCDA 41-50: BDBCEDAAAE 51-60: AAABBACECA Neco Physics ANSWERS By Nollywap. Nollywap.wapdale.com ================================== 1ai) i)Rockets are used for space travels. ii)Rockets are used for launching satellites into space 1aii) i)Artificial Satellites are used to send signals for televisions,radio, etc ii)Artificial satellites they are used for monitoring cloud patterns for a weather station 1b A propeller like piece called turbine is been rotated continuously by falling water from a dam, which then turns a metal shaft in an electric generator,which is the motor that produces electricity =================== 2a) CLICK HERE TO VIEW NO.2 IMAGE i)distance covered=5m+10m=15m ii)magnitude of his displacement =a^2=b^2+c^2 x^2=5^2+10^2=25+100 x^2=125 x=sqr125 =5sqr5m ==================== 4a) i)pulley ii)the inclined plane 4b) CLICK HERE TO VIEW NO4b IMAGE load------>fulcrum------>effort eg-crowbar ================= 5) V1=700cm^3, T1=30dgree-census+273=303k, P1=606mmHg V2=700-300=400cm^3, T2=47+273=320k from general gas law P1V1/T1 = P2V2/T2 606*700/303=P2*400/320 P2=606*700*320/303*400 P2=1120mmHg ================== 8a) Electric current is the rate of charge flow past a given point in an electric circuit, measured in Coulombs/second which is named Amperes. 8b) d=30cm,£=1.5*10^-5c r=30cm 30/100=0.3m V=kE/r=9*10^9*1.5*10^-5/0.3 =13.5*10^4 =13.5*10^5/3 V=4.5*10^5 V=450kv ================ 9a) i)by heating ii)electrical method 9b) energy stored=1/2CV^2 given that t C=4HF =4*10^-6F v=800v =1/2*4*10^-6*800*800 =2*800*800*10^-6 =1280000j*10^-6 =1.28j ================ 11) Tabulate -Hard Xray- i)high penetrating power ii)short wave length iii)produce high voltage -soft Xray- i)low penetrating power ii)long wave length iii)produced at low voltage ================= 12) CLICK HERE TO VIEW NO.12 IMAGE centre of gravity can be define as the point through which the line of action of the weight of the body always passes irrespective of the position of the body. 12b) C.g = centre of gravity :- v= u - gt Of maximum height v=O - K O= u-gt For vertical component, U =uSin tita Therefore O= usin tita- gt gt =uSin tita T=uSin tita/g Where T is the time taken to maximum height 12c) Taken moment about point A Cwm = {60*10)+ (20*60) Cwm=600+1200 Cwm=1800 Acwm = (20*40) + (R3 * 40) Acwm=800+80R3 At equilibrium, Cwm=Acwm 1800=800+40r3 1800-800=40r3 1000=40r3 R3=1000/40 R3=25N ==================== 13a) dew point is the temperature at which the water vapour present in the atmosphere is just sufficent to saturate it 13b) mist is formed as a result of condensed drops of moisture throughout the mass of cooled air. That is when water droplet in the air cool suddenly 13ci) the plastic comb will acquire electric charges 13cii) the plasic com can attract small pieces of paper due to the acquired charges 13di) area expansivity(B)=2§ =2*1.2*10^-5 B=2.4*10^-5 1k 13dii) given that initial length=6cm initial area A=6*6=36cm^2 rise in temperature =25k linear expansivity=1.2*10^-5/k area expansivity =2.4*10^-5/k new area At=Ao(1+Btita) At=36(1+2.4*10^-5*25) At=36(1+ 60*10^-5) At=36(1+0.0006) At=36(1.0006) At=36.0216 ================= 15a) electrical potential is the workdone in driving a unit charge of electric current from one point to another in a closed circuit. It is measured in volta(V) 15b) CLICK HERE TO VIEW NO.15b IMAGE A metal rod can be made into a magnet by divided touch me thod as shown in the diagram above. The metal rod is stroke at the middle with opposite pole end of two permanent magnets towards the opposite ends several times opposite polarity are then formed 15ci) CLICK HERE TO VIEW NO.15ci IMAGE VR=120v---->Vl=50v---->Vc=134.39v 220v,506z 15cii) V^2=Vr^2+(Vl-Vc)^2 220^2=120^2+(50-Vc)^2 48400=14400+(50-Vc)^2 48400=14400=(50-Vc)^2 34000=(50-Vc)^2 50-Vc=sqr34000 50-Vc=184.39 -Vc=184.39-5...............invite your friends