WAEC - Physics (1993)

1
Which of the following is not an example of a force?
Răspuns
(D)
Mass
2
A body moves along a circular path with uniform angular speed of 0.6 rad s^-1 and at a constant speed of 3.0ms^-1. Calculate the acceleration of the body towards the centre of the circle.
Răspuns
(D)
1.8 ms^-2
3
Which of the following is a derived unit?
Răspuns
(D)
Ohm
4
A body timed 20 oscillations of a certain pendulum three times and obtained 44.3s, 45.5s and 45.7s respectively. Calculate the mean period of oscillation of the pendulum
Răspuns
(C)
2.26s
5
A body of mass M1 moving with a velocity U collides with a stationary body of mass M2 and both move with a common velocity V lf linear momentum is conserved, which of the following expressions correctly represents V?
Răspuns
(A)
M₁ U/M₁ + M₂
6

A body of mass m = 0.5 kg is suspended by a string and pulled by a horizontal force of 12N as shown in the diagram. Calculate the tension T in the String if the body is in equilibrium. [Take g as 10ms\(^{-1}\)]
Răspuns
(D)
13.0
7
A particle starts from rest and moves with a constant acceleration of 0.5 ms^-2? Calculate the time taken by the particle to cover a distance of 25m.
Răspuns
(C)
10.0s
8
A block of material of volume 2 X 10\(^{-5}\)m\(^3\) and density 2.5 x 10\(^3\) kgm\(^{-3}\) is suspended from a spring balance with half volume of the block immersed in water. What is the reading of the spring balance? (Density of water =1.0x10\(^3\) kg m\(^{-3}\) g = 10 ms\(^{-2}\)).
Răspuns
(D)
0.40N
9
An object is projected with a velocity of 100 ms\(^{-1}\) from the ground level at an angle \(\theta\) to the vertical. If the total time of flight of the projectile is 10 s, calculate θ. (g = 10 ms\(^{-2}\)).
Răspuns
(D)
60^o
10
How far will a body move in 4 seconds if uniformly accelerated from rest at the rate of 2 ms^-2?
Răspuns
(C)
16m
11
If the temperature of water is gradually increased from 0^o to 4^oC, the density of the water within this range
Răspuns
(C)
increases gradually
12
The expansion of solids can be considered a disadvantage in the
Răspuns
(D)
balance wheel of a watch
13
A solid metal cube of side 10 cm is heated from
10^oC to 60^oC. lf the linear expansivity of the metal is 1.2 x 10⁵K^-1, calculate the increase in its volume.
Răspuns
(C)
1.8 cm³
14
A gas has a volume of 546 cm3 at OºC. What is the volume of the gas at -100ºC if its pressure remains constant?
Răspuns
(A)
346cm³
15
Which of the following are correct of plane- polarized light? I. Plane polarization of light is the formation of hydrogen bubbles on the particles of light. II. Plane polarization of light is the splitting of light into its spectral components III. Plane-polarized light vibrates in one plane only. IV. Polarization is characteristic of transverse waves.
Răspuns
(D)
III and IV only
16
Longitudinal waves cannot be
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(C)
polarized
17
An image which cannot be formed on a screen is said to be
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(C)
virtual
18
The images formed by a diverging lens are always
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(C)
diminished, virtual and erect
19
In the normal use of a simple microscope, a person sees an
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(B)
erect, virtual and magnified image
20
A lens of focal length 15.0 cm forms an upright image four times the size of an object. Calculate the distance of the image from the lens
Răspuns
(E)
75.0cm
21
An object is placed between two mirrors which are inclined at an angle of 120° and facing each other. Determine the number of images observed in the two mirrors
Răspuns
(B)
2
22
In a ripple tank experiment, a vibrating plate is used to generate ripples in the water. If the distance between two successive troughs is 3.5 cm and the wave travels a distance of 31.5 cm in 1.5 s, calculate the frequency of the vibrator
Răspuns
(B)
6.0Hz
23
Which of the following have the longest wavelengths?
Răspuns
(E)
Radio waves
24
A man stands in front of a tall wall and produces a sound. If he receives the echo of the sound two seconds later, calculate his distance from the wall. (The speed of sound in air is 330ms^-1)
Răspuns
(C)
330m
25
Which of the following is correct about light and sound waves?
Răspuns
(A)
Both of them are associated with energy transfer
26
The quality of a note produced by a vibrating string is determined by the
Răspuns
(A)
pitch of the note
27
Which of the following is a percussion instrument?
Răspuns
(C)
Bell
28
A short chain is usually attached to the back of a petrol tanker and trailing behind it so that the
Răspuns
(C)
charges generated by friction in the tanker are conducted to the earth
29
Which of the following indicates the correct sequence of steps taken in charging a gold-leaf electroscope by induction? l. Removing the ebonite rod ll. Bringing a negatively charged ebonite rod close to the cap III. Earthing the cap IV. Disconnecting the earthing
Răspuns
(D)
II, III, IV and I
30
Which of the following instruments can be used to compare the relative magnitude of similar charges on two given bodies?
Răspuns
(D)
Gold-leaf electroscope
31
The unit of inductance is
Răspuns
(B)
henry
32
A household refrigerator consumes electrical energy at the rate of 200 W. lf electricity costs 5 k per kWh, calculate the cost of operating the appliance for 30 days.
Răspuns
(A)
N7.20
33
Calculate the escape velocity of a satellite launched from the earth’s surface (Take g as 10ms^-2 and the radius of the earth as 6.4 x 10⁶m)
Răspuns
(B)
1.13 x10⁴ms^-1
34
What is the gravitational potential due to a point mass m at a distance from it? (G = gravitational constant)
Răspuns
(D)
–Gm/r
35
In a series R - C circuit, the resistance of the resistor is 4 Ω and capacitive reactance is 3 Ω. Calculate the impedance of the circuit
Răspuns
(C)
5Ω
36
The vector diagram shown below represents the resistance R, the capacitive reactance X_c, the inductive reactance X_c and the impedance, Z in an R-L-C circuit. The current in the circuit will be maximum when
Răspuns
(A)
X_c = X_c
37
In a purely resistive a.c. circuit, the current I = I_o sin wt and voltage, V = V_o sin wt. Calculate the instantaneous power dissipated in the circuit in time t.
Răspuns
(D)
I_o V_o sin²wt
38
A point charge of 1.0 x 10^-7 C experiences force of 0.01 N in a uniform electric field. Calculate the magnitude of the strength of the field
Răspuns
(B)
10⁵ Vm^-1
39
The potential difference between two points A and B situated at a distance d apart is V. Which of the following expresses the magnitude of the electric field intensity between the two points assuming the field is uniform?
Răspuns
(C)
Vd^-1
40
Which of the following have the greatest penetrating power?
Răspuns
(C)
Gamma rays
41
A particle of charge 5C moves perpendicularly to a magnetic Held of magnitude C.01 T. If the velocity of the charge is 1.5ms'2, calculate the magnitude of the force exerted on the particle
Răspuns
(B)
0.075N
42
The function of the magnanese (IV) oxide in a leclanche cell is to
Răspuns
(C)
prevent polarization in the cell
43
In the diagram above, three identical lamps each of 100 W are connected in parallel across a potential difference of 250 V. Calculate the reading of the ammeter.
Răspuns
(C)
1.2A
44
Electrical resistance is the property of an electrical conductor that causes electrical energy to be converted into
Răspuns
(C)
heat energy
45
Calculate the current, I in the diagram shown above.
(Neglect the internal resistance of the cell)
Răspuns
(C)
1.0A
46
Which of the following is not a conductor of electricity?
Răspuns
(B)
Glass
47
ln the diagram below, the galvanometer indicates a null-deflection. What is the potential difference between P and Q?
Răspuns
(A)
0.0 V
48
When a potential difference, V is applied across the ends of a resistor of resistance, R a Current, l passes through the resistor. The heat generated in the resistor in time, t is given by the expression
Răspuns
(C)
l²Rt
49
Electric motor primarily converts
Răspuns
(D)
electrical energy into mechanical energy
50
What amount of current would pass through a 10 Ω coil if it takes 21s for the coil to just melt a lump of ice of mass 10g at 0oC if there are no heat losses? (Latent heat of fusion of ice = 336 Jg\(^{-1}\)).
Răspuns
(B)
4.00 A
51
How long does it take a 750 W heater operating at full rating to raise the temperature of 1 kg of water from 40^oC to 70^oC? (Take the specific heat capacity of water as 4200 J kg^-1 K^-1 and neglect heat losses).
Răspuns
(C)
168s
52
24 Na → 24 mg⁴ + X + energy
11 2

The equation above represents a nuclear decay of sodium isotope. What is X?
Răspuns
(B)
Beta particle
53
lf Einstein’s photoelectric equation is represented by hf - W = Φ where h is Planck’s constant, f the frequency of incident radiation and W the work function of the material, what does the symbol Φ up stand for?
Răspuns
(B)
Maximum Kinetic energy of the ejected electrons
54
The phenomenon of radioactivity was first discovered by
Răspuns
(C)
Henn Becquerel
55
A radioactive substance has a half-life of 20 hours. What fraction of the original radioactive nuclide will remain after 80 hours?
Răspuns
(B)
\(\frac{1}{16}\)