 ## NECO Physics Practical Solution Questions and Answer – JUNE/JULY 2018 Expo Runz.

2)
Tabulate
Cos @ – |75|65|55|45|35|
MO(cm)- |1.1|2.0|2.5|3.4|3.9|
NO(cm)- |6.2|6.4|6.6|6.8|7.2|
H=MO/NO- |0.177|0.313|0.379|0.500|0.542|
Cos @ – |0.2588|0.4226|0.5736|0.7071|0.8192|
2aix)
From the graph
Slope
S =Δcostita/^ΔH
=0.75-0.45/0.5-0.3
=0.3/0.2
=1.5
2bi)
Snell’s law is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media, such as water, glass, or air.
i;e sini/sini=n
were n is known as refractive index
2bii)
given refractive index of glass =1.5
i;e a N g =1.5 (from air to glass)
sin C/sin90=gNa
sinC/sin90=1/aNg
sinC/1=1/1.5
since=0.6667
C=sin^-1(0.6667)
critical angle for glass,C =42degree
2biii)
i)I Ensured that the pins were vertical
ii)I Avoided parallax error when reading protractor.

3)
ii) Vo=2.00V
3v)
Tabulate
S/N – |1|2|3|4|5|
R(n) – |2|3|4|5|6|
V(v) – 2.10|2.30|2.40|2.50|2.60|
R^-1(n^-1)- |0.500|0.333|0.250|0.200|0.167|
V^-1(V^-1)- |0.476|0.435|0.417|0.400|0.385|
3aix)
3vii)
Slope
=Δv^-1/ΔR-1
=0.5 – 0.355/0.6 – 0
=0.145/0.6
S= 0.242
Intercept
C = 0.355v^-1
3aviii)
K= S/C
K= 0.242/0.355
K= 0.68
3ix)
i)I ensured that the terminals were firmly tight to prevent partial contact
ii)I avoided parallax error when taking reading from the voltmeter.

3bi)
i)temperature of wire
ii)cross-sectional area of wire
iii)length of wire
iv)nature of wire
3bii)
effective E.M.F =2V (parallel connection)
effective internal resistance =rxr/r+r=r/2 n
current I =0.8A
external Resistance R =2n
using
E=I(R+r)
2=0.8(2+r/2)
2.5=(2+r/2)
2.5-2=r/2
0.5=r/2
r=0.5×2=1n

COMPLETED – GOOD LUCK
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