WAEC - Physics (2007)

1
Which of the following observations is not an effect of surface tension?
Answer
(D)
water flowing out more easily then engine oil from a container
2
Which of the following physical quantities is correctly paired with it's corresponding S.I unit?
Answer
(B)
power[Js-1]
3
A liquid of volume 2.00 m3 and density 1.00 x 103 is mixed with 3.00 m3 of another liquid of density 8.00 x 103kg m-3. Calculate the density of the mixture [Assuming there is no chemical reaction]
Answer
(D)
5.20 x 103 kg m-3
4
Which of the following statements about solid friction are correct? It i. is a force ii. occurs between the surfaces of two bodies in contact iii. depends on the area in contact
Answer
(A)
i and ii only
5
A mass of mass m, experiences a viscous drag, F and an upthrust, U as he descends towards the ground at a steady velocity, Using a parachute. If the acceleration of free fall is g, which of the following expressions is correct?
Answer
(B)
U + F - mg = 0
6
a body moving at a constant speed accelerates when it is in
Answer
(C)
circular motion
7
An object of mass 2 kg moves with a uniform speed of 10ms-1 for 5s along an straight path. Determine the magnitude of its acceleration
Answer
(A)
0 ms-2
8
The team rectilinear acceleration means the rate of increase of
Answer
(D)
velocity along a straight-line path in a unit time
9
A body moving with an initial velocity U accelerates until it attains a velocity of V within a time t. The distance, s covered by the body is given by the expressions
Answer
(C)
s = (\(\frac{v + u}{2}\))t
10
A body accelerates uniformly from rest at 2ms-2. Calculate the magnitude of its velocity after travelling 9m
Answer
(B)
6.0ms-1
11
A swinging pendulum between the rest position and its maximum displacement possesses
Answer
(D)
both kinetic and potential energy
12
A block of mass 4.0kg causes a spiral spring to extend by 0.16m from its unstretched position. The block is removed and another body of mass 0.50kg is hung from the same spiral spring. If the spring is then stretched and released, what is the angular frequency of the subsequent motion? [g = 10 ms -2]
Answer
(A)
10\(\sqrt 5\) rads-1
13
An external force of magnitude 100N acts on a particle of mass 0.15kg for 0.03s. Calculate the change in the speed of the particle
Answer
(C)
20ms-1
14
A car of mass 800kg moves from rest on a horizontal track and travels 60m in 20s with uniform acceleration. Assuming there were no frictional forces, calculate the accelerating force
Answer
(A)
240.0N
15
A plane inclined at 30o to the horizontal has an efficiency of 50%. Calculate the force parallel to the plane required to push a load of 120N uniformly upn the plane
Answer
(B)
120.0N
16
Mechanical energy can be either
Answer
(C)
potential or kinetic
17
Which of the following surfaces will radiate heat energy best?
Answer
(C)
black surface
18
The ice and steam point on a mercury-in-glass thermometer are 10cm and 30cm respectively. Calculate the temperature in decree Celsius when the mercury meniscus is the 14cm mark
Answer
(A)
20oC
19
Which of the following statements distinguishes thermal conduction for convection? i. Conduction requires a material medium while convection does not ii. In convection, there is actual motion of hot material, while in conduction, molecules molecules vibrates faster about their mean positions iii. Conduction takes place in solids while convection takes place in fluids.
Answer
(B)
ii and iii only
20
A cube made of metal of linear expansivity \(\alpha\) is heated through a temperature \(\theta\). If the initial volume of the cube is Vo, the correct expression for the increase in volume of the cube is
Answer
(D)
\(3 \alpha V_o \theta\)
21
A relative density bottle of volume 50cm3 is completely filled with a liquid at 30oC. It is then heated to 80oC such that 0.75cm3 of the liquid is expelled. Calculate the apparent cubic expansivity of the liquid.
Answer
(A)
0.00030k-1
22
A body of mass 200g and specific heat capacity 0.4Jg-1k-1 cools from 37oC to 31oC. Calculate the quantity of the heat released by the body.
Answer
(C)
480J
23
According to the kinetic theory of gasses, which of the following property of a gas can be affected by the collision of the gas molecule with the walls of the container?
Answer
(D)
pressure
24
The pressure of a fixed mass of an ideal gas at 27°C is 3 pa. The gas is heated at a constant volume until its pressure is 5 pa. Determine the new temperature of the gas.
Answer
(B)
227oC
25
Which of the following wave is electromagnetic?
Answer
(A)
x-rays
26
The distance between two points P and Q, along a wave is 0.05m. If the wave length of the wave is 0.10m, determine the phase angle between P and Q in radians
Answer
(B)
\(\pi\)
27
Which of the following phenomena is not a direct consequence of rectilinear propagation of light?
Answer
(C)
diffraction of light
28
An object is placed 10cm in front of a plane mirror. If it is moved 8cm away father away from the mirror, determine the distance of the final image from the mirror
Answer
(D)
18cm
29
In which of the following piece of apparatus is the radius of curvature equal to twice the focal length?
Answer
(C)
converging mirror
30
When an object is placed at the centre of curvature of a concave mirror, its image is formed at
Answer
(C)
the centre of curvature
31
A rectangular glass prism of thickness d and absolute refractive index n is placed on a point object which is viewed vertically downward from above the prism. Which of the following expressions correctly defines the apparent upward displacement of the object?
Answer
(A)
\(\frac{d}{n}\)
32
Which of the following factors can affect the speed of sound in air? i. The temperature of the surrounding ii. The direction of the wind iii. The pitch of the sound.
Answer
(A)
i and ii only
33
A sounding tuning fork is brought near the open end of a pipe containing air and the loudness of the sound is observed to increase. This observation is due to
Answer
(B)
resonance
34
Which of the following statements about sound wave is not correct? Sound waves can be
Answer
(D)
polarized
35
A dry plastic comb used in combing hair was found to attract pieces of paper and dust. The most probable explanation for this phenomenon is that the comb has been given
Answer
(D)
electric charges by friction
36
Which of the following statements is correct about resonance? Resonance occurs when a body
Answer
(B)
is forced to vibrate on its own natural frequency by another body at the same vibration
37
Which of the following components is used for storing electric charges?
Answer
(C)
capacitor
38
Which of the following operations does not represent an action of a force field?
Answer
(D)
pushing of a wheel-barrow on a level gound
39
A bulb marked 240V, 40W is used for 30 minutes. Calculate the heat generated
Answer
(D)
72000J
40
Five 80-W and three 100W are run for 8 hours. If the cost of energy is N5.00 per unit, calculate the cost of running the lamp. [1 unit = 1 kWh]
Answer
(B)
N28.00
41
Which of the following electromagnetic wave can be detected by its heating effect?
Answer
(D)
infrared radiation
42
If a gas is excited by high voltage to produce a discharge and the light is examined in a spectrometer
Answer
(C)
an emission spectrum is observed
43
The number of protons in an element increased by one after a radioactive decay. The element must have decay by emitting
Answer
(A)
a beta particle
44
In a nuclear reactor, chain reactions result from the release of
Answer
(C)
neutrons
45
The correct sequence of energy transformation in the operation of an x-ray tube is i. X-rays ii. Kinetic energy of thermo electrons iii. Potential energy of the target atoms iv. Heat energy of the emitted electrons
Answer
(C)
iv, ii, iii, i