Waec Gce 2016 Physics Practical Answers

1a )
xi (cm )| yi (cm )| zi (cm )|W 1(Nx 10^ -2)|W 2 (Nx 10 ^ -2 )|u =(w 1 -w 2)(Nx 10 ^ -2)| v =(w 1 -w 3)(Nx 10 -2)
=>1 .80 |1 .50 |1 .70 |3 .6| 3. 00| 3. 40| 0. 60|0. 20
=>3 .80 |3 .00 |3 .00 |7 .6| 6. 00| 6. 00| 1. 60|1. 60
=>5 .50 |4 .40 |5 .00 |11 .10 | 8.00 | 10. 00 |2. 20 |1. 00
=>7 .30 |5 .90 |6 .60 |14 .60 | 11. 80 |13 .00 |2. 80 |1. 40
=>9 .20 |7 .30 |8 .30 |18 .40 | 14. 60 |16 .60 |3. 80 |1. 80
=>11 .10 | 8.30 | 10. 00 |22 .20 |16 . 60| 20 .00 |5. 60 |2. 20



1b)Relative density, or specific
gravity, is the ratio of the
density (mass of a unit
volume) of a substance to the
density of a given reference
material. Specific gravity
usually means relative
density with respect to water.


1bii) given volume of solid immersed
Vsi =1/2*30cm³
=15cm³
Density of liquid (water)ew= 1g/cm³
Acceleration due to gravity, g = 10m/s²
Upthrust, U= eVsi g
U= 1000*(15*10^-6)*10
U=15*10-²
U=0.15N

Weight of solid =mg
=EsVs g
given: Es=2.4g/cm³ (2400kg/m³)
Vs=30cm (30*10^-6 m³)
g=10m/s²

Weight, w=30*10^-6*2400*10
=72*10-²
=0.72N
Reading on spring balance =W-U
=0.72-0.15
=0.57N
======================





2bi)-It is used for Magnifying glass:
For a magnifying glass to work, the object is
placed at the focal point such that the image
produced is magnified, upright and virtual.

- It is used in aSlide projector: a projector essentially uses a
convex lens to form on a screen a real, magnified
and inverted image of the slide or film. The slide,
being the object, is positioned between the j and 2f
from the lens.
=====================




3) | R/n | I(A) |P=E/I V n^-1
1. |0.00| 3.00 |0.500
2. |1.00| 1.00.|1.500
3. |2.00| 0.60 |2.500
4. |3.00|0.45. |3.333
5. |4.00|0.35. |4.286
6. 5.00 |0.25. |6.000

3vi)
S=y2-y1/x2-x1
=4-2/3.6-1.5
=2/2.1
=0.952

3vii) C=0.5ohms

3Viii)Resitance

3ix)-I ensured that the circuit is open after each reading to maintain the E.M.F of the battery

-I ensured that the Zero Error of the Ammeter is checked and noted




3b)Internal resistance of a cell is the resistance within a
battery, or other voltage source, that causes a
drop in the source voltage when there is a
current. There is, therefore, actual reduction in
the electromotive force of the cell , as well as an
increase in internal resistance.
======================