2019 WAEC EXPO PHYSICS PRACTICAL QUESTIONS AND ANSWERS

2019 PHYSICS PRACTICAL ANSWERS

(1aviii)
In a tabular form
Under y(cm)
20.0, 30.0, 40.0, 50.0, 60.0

Under t(s)
36.61, 33.66, 31.32, 28.62, 25.93

Under T = t/20(s)
1.8305, 1.6830, 1.5660, 1.4310, 1.2965

Under T²(s²)
3.3507, 2.8325, 2.4524, 2.0478, 1.6809

(1ax)
Slope s = ΔT²/Δy
S = 4 – 2.5/0 – 39
S = 1.5/-39
S = -0.0385

Intercept, C = 4.0

(1axi)
SR = c
R = c/s = 4/-0.0385 = -103.9

(1axii)
(i) I ensured that the retort stand was well clamped.

(ii) I avoided error due to parallax when reading the metre rule.

(3ai)
E.m.f, E = 3.00v

(3avii)
In a tabular form
Under R(ohms)
2.0, 5.0, 10.0, 12.0, 15.0, 20.0

Under V(v)
0.86, 0.62, 0.43, 0.38, 0.32, 0.25

Under V-¹(v-¹)
1.1628, 1.6129, 2.3256, 2.6316, 3.1250, 4.0000

(3aix)
Slope s = ΔR/Δv-¹
=17.5 – 4.25/3.5 – 1.5
=13.25/2
=6.625

Intercept, C = -5.75

(3ax)
S = Roα
6.625 = 0.85(α)
α = 6.625/0.85 = 7.79

C = -(Ro + β)
= -5.75 = -(0.85 + β)
β = 5.75 – 0.85
β = 4.9

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

(3bi)
Vab = 12 – 8 = 4v
Rab = 4×5/4+5 = 20/9ohms
Iab = Vab/Rab = 4/20/9 = 4 ×9/20 = 9/5
=1.8A

Power = I²ab Rab
=1.8² * 20/9
= 7.2watts

(3bii)
Current in line = power/voltage = 3600/240
=15A
Circuit breaker remain closed because current in line is less than 20A

Advertisements

we will get back to you shortly...!

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s