# 2019 NECO EXPO RUNZ PHYSICS PRACTICAL QUESTIONS AND ANSWERS

=-=-=-=-=-=-=-=-=-=-==-=-=-=-=-=-

NECO 2019 PHYSICS PRACTICAL ANSWERS FROM EXAMCLASS.NET
–=-=-=-=-=-=-=-=-=-=-==-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

Physics PRACTICAL
-=-=-=-=-=-=-=-=-=-=-=-==-=-=-=-=-=-=-=-=-=-=-==-=-=-=-=-=-=-=-=-=-=-=

(1a)
Centre of gravity C G = 50.0cm

(1aviii)
Tabulate:
Under Y(cm): 10; 15; 20; 25; 30;
Under K(cm): 32.7; 35.0; 37.0; 39.0; 41.0;
Under X(cm): 22.7; 20.0; 17.0; 14.0; 11.0;
Under K¹(cm): 29.0; 31.5; 34.3; 36.9; 39.5;
Under X¹(cm): 19.0; 16.5; 14.3; 11.9; 9.5;

(1axii)
(i)i avoided drought by closing the window
(ii)i avoided error due to parallax when reading the meter rule

(1bi)
Couple is a pair of forces, equal in magnitude, oppositely directed, and displaced by perpendicular distance or moment.

(1axii)
(i)i avoided drought by closing the window
(ii)i avoided error due to parallax when reading the meter rule

(1bi)
Couple is a pair of forces, equal in magnitude, oppositely directed, and displaced by perpendicular distance or moment.

(1bii)
Draw the diagram
Sum of clockwise moment = sum of anticlockwise moment
0.2m = 50 × 0.5
m = 50×0.5/0.2
m = 125g
Mass of beam = 125g

-=-=-=-=-=-=-=-=-=-=-=-==-=-=-=-=-=-=-=-=-=-=-==-=-=-=-=-=-=-=-=-=-=-

(2xiv)
– I ensure both the object and the pin were in straight lines so as to avoid error due to parallax
– I ensured that all the pins were vertically placed

Typinq…

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-==-=-=-

(3av)
E=3.0v

(3avii)
Tabulate

Under L(cm): 20.0; 30.0; 40.0; 50.0; 60.0; 70.0;
Under I(A): 0.70; 0.60; 0.55; 0.50; 0.45; 0.40;
Under X=E/I(Ohms): 4.2857; 5.0000; 5.4545; 6.0000; 6.6667; 7.5000;

(3aix)
slope = ΔL/ΔX = 66 – 12/7 – 4
= 54/3 = 18cm

Intercept, C

(3ax)
K = 4.9×10^-7
K = 4.9×10^-7 × 18
K = 8.82×10^-6cm/ohm

(3axi)
-I ensured tight connections.
-I avoided error due to parallax on the ammeter.

(3bi)
-Keep the top or terminals clean.
-Do not tighten or remove cables while charging or discharging.

(3bii)
Using ohm’s law
R = V/I = 3.5/0.25 = 14ohm

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-==-=-=-

-=-=-=-=-===-=-=-=-=-=-=-=-=-=-==-=-=-=-=-=-=-=-=-=-=-=-=-=

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-==-=-=-=

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-==-=-=-=

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-==-=-=-=

=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

=-=-=-=-==-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

============================================

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=

-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=