Neco Physics Practical Answers – June/July 2019 Runs

Neco Physics Practical Answers – June/July 2019 Runs

(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;

(1ax)
Slope = ΔX/ΔX1 = 16 – 8/13.4 – 6.8 = 8/6.6 = 1.21

(1axi)
K = M1 – Sm/S – 1
= 150 – 1.21(100)/1.21 – 1
= 150 – 121/0.21
= 29/0.21
=138

(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

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(NUMBER 3)

(3bi)
Lost volt is the voltage lost due to
the internal resistance of a cell.
It is measured in volts

(3bii)
E= I(R+r)
4=I(2+0.5)
4=2.5I
I=4/2.5
I=1.6A

(3viii)
(Pick two)
(Precaution)

(i)I would ensure that the key is
opened when circuit is not in use
to avoid the cell being used up

(ii)I would ensure that the
electrical wires are tightly
connected

(iii)I would ensure clean
terminals

(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

_________________________________
Q1.
determine the slope of the graph
and the intercept c
– evaluate k1 = k1 = 4π2/s and k2
=
(Xiii)- state any two of the
following precautions
– Avoided conical oscillations
– Ensured firm suspension of
pendulum
– Ensured reading is repeated
(shown on the table
– Avoided draught
-Corrected/noted for zero error
of metre rule/ stop match/clock
– Avoided parallax error in
reading metre rule/ stop clock

(b) (i) The period of oscillation of
a body is the time taken for the
body to make one complete to
and from movement

(ii) When a body is falling under
its weight (alone), the rate of
increase of its velocity with time
(as a result of the earth’s
gravitational pull) is the
acceleration of free fall due to gravity

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