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WAEC GCE 2017 Physics Expo Answers (Nov/Dec Expo) 1 A 2 B 3 A 4 B 5 D
6 B 7 B 8 B 9 – 10 –
11 – 12 D 13 C 14 D 15 A
16 D 17 C 18 A 19 B 20 –
21 B 22 C 23 B 24 C 25 A
26 A 27 D 28 A 29 C 30 D
31 A 32 D 33 B 34 C 35 D
36 A 37 C 38 B 39 B 40 B
41 B 42 D 43 A 44 A 45 C
46 A 47 A 48 B 49 C 50 A

Question one
(a) Horizontal speed just before it strikes floor = ucos(theta)
= 10cos0°
= 10 m/s

(b) t = √(2g/h)
= √(2*10*1)
= √20
= 4.47s

Question 4
(a) given: u = 20m/s
t = 4s
g = 10m/s²
h = ?
Using s = ut – ½gt²
s = 20(4) – ½(10)(4)²
s = 0m

(b) The inference is that after 4s, the ball returns back to the plane of projection

Question 3
Magnetic materials: ¶ Iron ¶ Cobalt ¶ Nickel

Question 2
¶ medical uses
¶ welding and cutting
¶ military uses for defense and counter measures

Question 5
The factors that determine the location of a solar power station are
¶ Intensity of sun light
¶ surface slope
¶ feeder capacity of the distribution center

Physics
8ai)

Force is a push or pull which changes a body’s state of rest or uniform motion in a straight line.

II)a) field force
b) contact force
=================
8bi)
Bodies streamlined in
Shape move through fluid so as to oppose or overcome the motion of the fluid

II) a) fish
B) submarine
==================
8c)

Mass= 1.3 kg
F= 1.2 m
V= 7.0 m/s

Drawing

II) Acceleration
Note , V²= U² + 2as

Where S=r=1.2 m

(7.0)²= 0²+2× a (1.2)

= 49/2.4 = 2.4a/2.4

a = 20.4

B) Force=?
From force = MA
Force =1.3×20.4
Force =25.52
=========={={{{{{{============

*Question 9*
(a) Poor conductors of heat application: ¶ Coat (Trapped air in between the fabric)
¶ The hair and the fur of animals are bad conductors of
heat and they protect them from cold .

(b) Renewable: Water, corn stalk
Non-renewable: coal, natural gasgas

(c) A closed is a physical system so far removed from other systems that it does not interact with them.

d) heat required to melt = mc∆ + ml
*NB*: Not sure of the temperature given, if it is -3°C or -5°C, However, *Using -3°C*
Heat = (0.1×2200×3)+(0.1×2.26×10^6)
= 226660 J

e) (i) Given: 75 heart beats in 1 min
Therefore in 1 hour, we have (75×60) heart beats = 4500 heart beats
Also given: 2J of energy is expended in 1 heart beat
Therefore for 4500 heart beats, energy expended = (4500×2) J = 9000J

e) (ii) Energy = mc∆
9000 = (0.25×4200×∆)
9000 = 1050∆
∆ = 9000/1050
Temperature rise = 8.57°C
========={={{===================
*Question 11*

(a) ¶ Electrical method
¶ Contact method

(b) Electric lines of force are imaginary lines drawn in an electric field in such a way that the direction at any point gives the direction of the electric field at such a point

(c) QR = SP

(d) Resistivity is the resistance of a unit length of material of unit cross-sectional area

d) heat required to melt = mc∆ + ml
*NB*: Not sure of the temperature given, if it is -3°C or -5°C, However, *Using -3°C*
Heat = (0.1×2200×3)+(0.1×2.26×10^6)
= 226660 J

(e) Given: F = 50Hz
L = 10 mH (10×10^-³H)
Inductive reactance, XL = 2πFL
= 2×3.14×50×10×10^-³
= 3..14 ohms

(f) If voltmeter reads 12V, over the 500 ohms, then using I = V/R
current in the circuit is I = 12/500
I = 0.024A
Hence over the 200 ohms, V = IR
V = 0.024×200
V = 4.8 VOLTS

(9a)
(i) Coat (Trapped air in between the fabric)
(ii) The hair and the fur of animals are bad conductors of heat and they protect them from cold .

(9b)
-Renewable: Water, corn stalk
-Non-renewable: coal, natural gasgas

(9c)
A closed is a physical system so far removed from other systems that it does not interact with them.

(9d)
Heat required to melt = mc∆ + ml
NB: Not sure of the temperature given, if it is -3°C or -5°C, However, Using -3°C
Heat = (0.1×2200×3)+(0.1×2.26×10^6)
= 226660 J

(9ei)
Given: 75 heart beats in 1 min
Therefore in 1 hour, we have (75×60) heart beats = 4500 heart beats
Also given: 2J of energy is expended in 1 heart beat
Therefore for 4500 heart beats, energy expended = (4500×2) J = 9000J

(9eii)
Energy = mc∆
9000 = (0.25×4200×∆)
9000 = 1050∆
∆ = 9000/1050
Temperature rise = 8.57°C

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

(10a)
(i) Plane waves
(ii) Spherical waves
-For plane waves -Their dipper are wooden strip
-For spherical wave – Their dipper are spherical ball

(10b)
White and are actual colours of light because both white and black are centralof additive and substractive

(10c)
A yellow object is illuminated with green liight and when viewed through a yam filter becomes white since the colours consist of both primary and secondary colours which are known as complementary colours

(10d)
f0=V/2l
2f0l=V
l=V/2f0
=330/(2*400)
l=330/800
0.41m
10e)
f=200khz
Period T=1/f
T=(1/200*10^3)s
Period T=5*10^-6s
?

(11a)
(i) Electrical method
(ii) Contact method

(11b)
Electric lines of force are imaginary lines drawn in an electric field in such a way that the direction at any point gives the direction of the electric field at such a point

(11c)
QR = SP

(11d)
Resistivity is the resistance of a unit length of material of unit cross-sectional area

(11e)
Given: F = 50Hz
L = 10 mH (10×10^-³H)
Inductive reactance, XL = 2πFL
= 2×3.14×50×10×10^-³
= 3.14 ohms

(11f)
If voltmeter reads 12V, over the 500 ohms, then using I = V/R
current in the circuit is I = 12/500
I = 0.024A
Hence over the 200 ohms, V = IR
V = 0.024×200
V = 4.8 VOLTS

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