Saturday October 23, 2021

# 2021 WAEC Physics Practical Alternative A Question And Answer

2021 WAEC Physics Practical Alternative A Questions And Answers

Two metre rule
Retort stand and clamp

Stopwatch/clock

A weighing balance;
Split cork.

Question 2

(1) Ray box with illuminated objects (cross wire)
(2) Convex lens(f = 15cm)

(3) Screen
(4) Metre rule.
(5) Lens Holder.

Question 3
Accumulator (2×1.5v)
Ammeter (0 – 1A)

Crocodile clip
A 2 ohms Q resistor
Key
Connecting wires

(1)
TABULATE:
S/N: 1,2,3,4,5
M(g):40.0,60.0,80.0,100.0,120.0

x(cm):37.50,25.0,18.75,15.00,12.50
x^-1(cm^-1):0.027,0.40,0.053,0.067,0.08

x^-1(*10^-3):27.00,40.00,53.00,67.00,80.00
Note: G=50.0cm Y=30.0cm

(1a)
(xi) PRECAUTIONS
(i) I ensured that the meter rule balances horizontally before readings are taken in order to avoid experimental error.

(ii) I ensured that parallax error was avoided when taking the readings on The meter rule by viewing its calibration vertically.

(1bi) Moment of a force can be defined as the product of the force and its perpendicular distance from its point of action.
Moment of a force = force * Perpendicular distance of its line of action from the point
Moment = F * L

The S.I unit is Newton-meter(Nm).
It is a vector quantity

(1bii)

x=50-25
=25cm.

y=80-50
=30cm.

From the principle of moment:
Sum of clockwise moment = Sum of anti-clockwise moment

60 * x=m * y
60 * 25 = m * 30
Divide both sides by 30

60 * 25/30 = m *30/30
m=60 * 25/30
m=2 * 25
m=50g.

(2)

(3a)
(i) E=3.00v
TABULATE.

R(ohms) | I(A) | V(v)
1.0 0.40 0.65
2.0 0.35 0.58
4.0 0.28 0.50

6.0 0.22 0.45
8.0 0.18 0.40

(3aix)
(i) I avoided error due to parallax when reading the ammeter and voltmeter.
(ii) I ensured tight connections.

(3bi)
(Pick any 2)
(i) connecting cells in parallel adds the current capacities together.

(ii) connecting cells in parallel provides alternative Pathways for Current flows.
(iii) When cells are connected in parallel the Total voltage provided do not change

(3bii)
(Pick any 2)
(i) Resistance.
(ii) Tolerance.

(iii) Rated Power Dissipation.
(iv) Package and mounting.
(iv) Voltage rating.