# 100% CORRECT 2018 NECO GCE PHYSICS PRACTICAL ANSWERS HERE!

1bii

It’s because an iron ship is not completely solid. It has full of air filled in it. So the average density of the ship as a whole is less than the density of water. Therefore immersed portion of the ship displaces water equal to its weight. So the ship floats whereas a sheet of iron is compact and there are no air spaces inside it. Iron is denser than that of water. The weight of the sheet is greater than the weight of the water displaced by the sheet. So it sinks

2bi) I Rainbow
II Wave length
2v)
SLOPE​
Slope,s =y2-y1/x2-x1
=56.7-20/4-1
=36.7/3
=12.233
=12.23
2vi)U = 100/S = 100/12.23
= 8.176
=8.18
2vii)
– I will avoid error due to parallax while reading the meter rule.
-I will ensure the mass is kept dried before weighing

3a)Readings
1 | R(ohms) | R^-1(ohms)| L(cm) | L(cm)

1 | 1.00 | 1.000 | 13.50 | 0.074
2 | 2.00 | 0.500 | 27.50 | 0.036
3 | 3.00 | 0.333 | 41.50 | 0.024
4 | 4.00 | 0.250 | 55.00 | 0.018
5 | 5.00 | 0.200 | 69.00 | 0.014
Note:where u see ohms put the ohms sign
(3av)
Slope=Change in R^-1/Change in L^-1

=(0.500-0.200)/(0.036-0.018)

S=0.30/0.018

=16.67cm/n

(3avi)

Rs=100/16.67

Rs=5.99880n/cm

Rs=6.0n/cm