NECO GCE PHYSICS PRACTICAL 2017/2018

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 

 2bii)M=V/U object height=8cm Image height=192cm M=192/8 M=24cm 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 

2aiv) -I ensured tight connections -I avoided error due to parallax when reading the voltmetre -I ensured the key is opened after each reading to prevent the cell from running down 

---

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