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   DIR Return to: WAEC/NECO 2016/2017 UPDATE
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       #Post#: 23--------------------------------------------------
       WAEC 2016 VERIFIED PHYSICS ANSWERS
   DIR By: anephy
       Date: April 12, 2016, 4:28 am
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       PHYSICS ANSWERS
       (Note: This symbols ^ means Raise to
       power)
       10a)
       Critical angle is the angle of incidence in
       the
       optically densed medium when the
       angle of
       refraction is 90degrees
       10b)
       Anti-note are created by region of
       maximum
       displacement in a wave more coming
       ================================
       11a)
       Dielectric strength is the property of an
       insulating
       material to retain material to retain
       electrical
       properties
       11bi)
       -Infra-red wave
       -Geiger muller counter
       -Scintillation counter
       11bii)
       Irradiation of solar energy
       11c)
       Charge(q)=1.0*10^-19C
       Electric field intensity(E)=1200NC^-1
       Weight of the oil drop=?
       E=F/q
       1200=F/1.0*10^-19 F=1200*1.0*10^-19
       F=1.2*10^3*10^-19
       F=1.2*10^-16N
       11d)
       R=100ohm, L=0.05H, C=0.25uF
       V=220v, f=50Hz
       11di)
       Impedance(z)=sqroot(R^2+(Xl-Xc)^2)
       Xl=2*pie*fl
       Xl=2*(22/7)*50*0.05
       Xl=15.71ohm
       Xl=(1/2*pie*fc) Xc=1/78.55*10^-6
       Xc=10^6/78.55
       =12730.7ohm
       Z=sqroot(100^2+(15.71^2-12730.7^2)
       Z=sqroot(10000+2.63*10^16
       Z=sqroot(2.63*10^16)
       Z=1.62*10^16ohm
       11dii)
       Vrms=IZ
       I=220/1.62*10^16
       =1.36*10^-14
       ================================
       9a)
       i) thermal equilibrium is the point at
       which the
       temperature of an object remain
       constant or steady
       ii)fundamental interval is the distance
       between
       upper and lower fixed point of a
       thermometre
       9b)
       i) it can be used to raise heavy load
       ii) it is used in printing press
       9c)
       magnet
       9di)
       by using calometry law
       heat last = heat gain
       MmCmDθm=CaDθ + Mw Cw Dθ
       300 * Cm * ( 85 - 40 ) = 90 + 500 * 4200
       13500Cm = 90 + 29400000 13500CM =
       29400090/13500
       Cm=2177.78Jg^-K^-1
       9dii) §
       i) by convection
       ii) by conduction 9diii) §
       i) power generation
       ii) chemical processing
       ========================
       5)
       i) For launching astronauts into the
       space
       ii) For launching satellite
       iii) For Scientific research
       ================================
       6a)
       Doping is the addition of small quantity
       of an
       element to a semi conductor to change
       its
       characteristics
       6b)
       Doping introduce impurities into an
       extremely pure
       instrintic semi conductor for the purpose
       of
       modulating its elctrical properties
       ================================
       7)
       X = Electron gun
       Y = Accelerating mode
       Z = Deflection plate
       ================================
       3)
       -smoke -aerosol
       -dust particle
       ================================
       1a)
       impulse(I)=F*t
       F=ma= m(v/t)= M((d/t)/(t)) f=M(l/T)/T)=
       MLT^-2
       I=MLT^-2 * T
       I=MLT^-1 1b)
       Acceleration(a)=v/t=(d/t)/t
       a=d/t^2= L/T^2= LT^-2 1c)
       WOrk(w)=f*d
       W=MLT^-2 * L
       W=ML^2T^-2
       ================================
       4)
       Given flux density(B)=0.217
       Force(F)=9.6*10^-12N
       Speed(v)=?
       F=Bqv 9.6*10^-12= 0.12* 1.6* V
       V=(9.6*10^-12)/0.192*10^-19
       =50*10^-12+9
       v=50*10^7
       =5*10^8ms^-1
       ================================
       2)
       Velocity(u)=20ms^-1
       Angle(tita)=40 degree
       At maximum height, h
       V^2=u^2 + 2gh
       U^2 sin^2 tita+u u= 20^2* (sin 40
       degree)^2
       u=20^2*(sin 4o degree)
       u=400* 0.3455
       u=138.2ms^-1
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