Physics 3 (Practical Alternative A) Waec 2017/2018 Expo

Physics 3 (Practical Alternative A)  Waec 2017/2018 Expo Answers




NOTE: ^ means raise to power

1) TABULATE:
i:1,2,3,4,5,
L(cm):80.00,70.00,60.00,50.00,40.00 t1(s):17.87,16.22,16.09,14.08,13.28 t2(2):17.56,16.46,15.09,14.77,13.36 t(s)mean:17.715,16.340,15.590,14.425,13.320
T(t/10)s:1.7715,1.6340,1.5590,1.4425,1.3320
LogT(s):0.2483,0.2133,0.1928,0.1591,0.1212
Log L(cm):1.9031,1.8451,1.7782,1.6990,1.6021
Log T*10^-2(s):24.83,21.33,19.28,15.91,12.12 Log
L*10^-1(cm):19.031,18.451,17.782,16.990,16.0
SLOPE(s)=(LogT2*10^-2 – LogT1*10^-2)(/Log L2 *10^-1 – LogL1*10^-1)
=(21.33-12.12(s))*10^-2/(18.50-16.02(cm)*10^-1)
=3.714*10^-1 =0.3714cm^-1




—————————————————————- 1axi)

i)ensured supports of pendula were rigged

ii)avoided parallax error on meter rule/stop watch



1bi) simple harmonic motion is the motion of a body whose acceleration is always direct towards a fixed point and is proportional to the displacement from the fixed points



1bii) T=1.2secs Log 1.2=0.079 0079 shown on graph with corresponding Log L read L correctly determined






3a)

TABULATE
x(cm):10,20,30,40,50,60
V(v):0.65,0.75,1.00,1.20,1.45,1.55
I(A):0.20,0.30,0.35,0.40,0.45,0.55
LogV(v):-0.187,-0.125,0.000,0.079,0.161,0.190
LogI(ohm):-0.699,-0.523,-0.456,-0.396,-0.391,-0.36
SLOPE(s):=( LogI2-LOgI1)/(LogV2-LogV1) =-0.2-(-0.7)/0.3-(-0.2) =0.5/0.5 =1AV^-1

3axi)

i)ensured clean/tight terminals

ii)open key when reading was taken

3bi)

i)brightness of the bulb increases

ii)voltage/current through the bulb increases

3bii) i)diode

ii)transistor



3)

*Precaution for electricity* i)I avoid parallax error when reading ammeter and voltmeter.
ii)I ensure tight connection
iii)I open the key when reading and not taken to ensure that cells do not run down
iv)I ensure that the jockey is not dragged alone the potentiometer wire