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WAEC - Physics (2000)

  • 1

    The diagram above illustrates three forces T\(_1\), T\(_2\) and 100N in equilibrium. Determine the magnitude of T\(_1\).

    คำตอบ
    (A)
    100 tan 30o
  • 2
    An iron rod is moved from the earth to the moon. Which of the following properties of the rod would remain unchanged? i. mass ii. weight iii. relative density
    คำตอบ
    (D)
    i and iii only
  • 3
    A uniform cylindrical hydrometer of mass 20g and cross sectional area 0.54cm2 floats upright in a liquid. If 25cm of its length is submerged, calculate the relative density of the liquid. (Density of water = 1 gcm-3)
    คำตอบ
    (B)
    1.48
  • 4
    The apparent weight of a body wholly immersed in water is 32N and its weight in air is 96N. Calculate the volume of the body. (Density of water = 1000kgm-3, g = 10ms\(^{-2}\))
    คำตอบ
    (B)
    6.4 x 10-3m3
  • 5
    A wooden block of mass 1.6kg rests on a rough horizontal surface if the limiting friction force between the block and the surface is 8N. Calculate the coefficient of friction. (g = 10ms-2)
    คำตอบ
    (B)
    0.5
  • 6
    A ball bearing is gently released from rest and allowed to fall through a viscous fluid. Which of the following statements about the motion is correct?
    คำตอบ
    (A)
    its acceleration decreases before terminal velocity is attained
  • 7
    The driver of a car moving with uniform speed of 40ms-1 observes a truck approaching from the opposite direction with a speed of 20ms-1. Calculate the speed of the car relative to that of the truck
    คำตอบ
    (D)
    60.0ms-1
  • 8
    A bus travelling at 15ms\(^{-1}\) accelerates uniformly at 4ms\(^{-2}\), what is the distance covered in 10s?
    คำตอบ
    (C)
    350m
  • 9
    A uniform metre rule of mass 90g is provided at the 40cm mark. If the rule is in equilibrium with an unknown mass m placed at the 10cm mark and a 72g mass at the 70cm mark, determine m
    คำตอบ
    (B)
    102g
  • 10
    The resultant of two forces acting on an object is maximum when the angle between them is?
    คำตอบ
    (D)
    0o
  • 11
    The bob of a simple pendulum takes 0.25s to swing from its equilibrium position to one extreme end. Calculate its period
    คำตอบ
    (D)
    1.00s
  • 12
    The period of oscillation of a particle executing simple harmonic motion is 4\(\pi\) seconds. If the amplitude of oscillation is 3.0m. Calculate the maximum speed of the particle.
    คำตอบ
    (A)
    1.5ms-1
  • 13
    An inelastic collision takes place between ball of known masses, just before the collision one of the ball is moving with a known velocity while the other is stationary. Which of the following physical quantities can be determined from the information given?
    คำตอบ
    (D)
    total momentum of the two ball after collision
  • 14

    Using the force displacement diagram shown above. Calculate the work done

    คำตอบ
    (B)
    1000J
  • 15
    A machine of efficiency 80% is used to raise a body of mass 75kg through a vertical height of 3m in 30s. Calculate the power input. (g = 10ms-2)
    คำตอบ
    (D)
    93.8W
  • 16
    Two bodies P and Q, are in thermal equilibrium, which of the following statements about the bodies is correct?
    คำตอบ
    (D)
    P and Q are at the same temperature
  • 17
    The cubic expansivity of mercury is 1.8 x 10-4K-1 and the linear expansivity of glass 8.0 x 10-6K-1, calculate the apparent expansivity of mercury in a glass container
    คำตอบ
    (B)
    1.56 x 10-4K-1
  • 18

    The diagram shows the variation of volume V of a glass with temperature at the point X is

    คำตอบ
    (C)
    -273oC
  • 19
    The volume and pressure of a given mass of gas at 27oC are 76cm3 and 80cm of mercury respectively. Calculate the volume at s.t.p
    คำตอบ
    (B)
    72.8cm3
  • 20
    A piece of metal of mass 50g is cooled from 80oC to 20oC. Calculate the amount of heat lost. (specific heat capacity of the material of metal = 450Jkg-1K-1)
    คำตอบ
    (D)
    1.35 x 103J
  • 21
    The mass of water vapour in a given volume of air is 0.05g at 20oC, while the mass of water vapour required to saturate it at the same temperature is 0.15g. Calculate the relative humidity of the air
    คำตอบ
    (C)
    33.33%
  • 22
    The temperature at which the saturated vapour pressure of a liquid is equal to the external atmospheric pressure is known as its
    คำตอบ
    (B)
    boiling point
  • 23
    A periodic pulse travels a distance of 20.0m in 1.00s. If its frequency is 2.0 x 103Hz. Calculate the wavelength.
    คำตอบ
    (B)
    1.0 x 10-2m
  • 24
    A wave has an amplitude equal to 4.0m, angular speed \(\frac{1}{3} \pi\) rads-1 and phase angle \(\frac{2}{3} \pi\) rad. The displacement y of the wave particle is given as
    คำตอบ
    (A)
    y = 4 sin \(\frac{\pi}{3}\)(t + 2)
  • 25

    In the diagram above, an incident ray AY makes an angle of 30o with the normal XY. If the mirror is rotated anticlockwise about Y through an angle of 20o, while AY is fixed, what angle will the reflected ray now make with the incident ray?

    คำตอบ
    (C)
    100o
  • 26
    A concave mirror can be used to produce a parallel beam of light if a lighted bulb is placed
    คำตอบ
    (B)
    at its focus
  • 27
    A simple microscope forms an image 10cm from an eye close to the lens. If the object is 6cm from the eye, calculate the focal length of the lens
    คำตอบ
    (A)
    3.75cm
  • 28
    When white light passes through a triangular glass prism, there is dispersion because of
    คำตอบ
    (C)
    the difference in speed of the components of light
  • 29
    In which of the following media does sound travel faster?
    คำตอบ
    (B)
    brass
  • 30
    A turning fork of frequency 600Hz is sounded over a closed resonance tube. If the first and second resonant positions are 0.130m and 0.413m respectively, calculate the speed of sound in air
    คำตอบ
    (C)
    339.6ms-1
  • 31
    loudness increases as a vibrating tuning fork is brought nearer the end of a pipe containing air column due to
    คำตอบ
    (A)
    resonance
  • 32
    the factor which enables the ear to distinguish between a note played on different instruments is the
    คำตอบ
    (C)
    harmonics
  • 33
    An object is situated within the Earth's gravitational field. Which of the following factor does not affect the acceleration of free fall g?
    คำตอบ
    (D)
    the mass of the object
  • 34
    The capacitance of a parallel-plate capacitor is increased by making the area of the plates
    คำตอบ
    (B)
    large and their seperation small
  • 35

    In the diagram above, the current passing through the 6\(\Omega\) resistor is 1.5A. Calculate the current in the 3\(\Omega\) resistor

    คำตอบ
    (D)
    0.60A
  • 36
    An immersion heater is rated 120W. How long does it take the heater to raise the temperature of 1.2kg of water by 15oC. (Assuming heat lost to the surrounding is negligible. Specific heat capacity of water = 4200 Jkg-1K-1C)
    คำตอบ
    (D)
    10.5 minutes
  • 37
    The region around a magnet in which the magnetic influence is experienced is called
    คำตอบ
    (B)
    magnetic field
  • 38
    A device used to prevent wearing away of the make and-brake contacts of an induction coil is called a\an
    คำตอบ
    (D)
    capacitor
  • 39

     

    If a bar magnet is accidentally broken into three pieces as shown in the diagram above, the polarities of P and Q respectively are

     

    คำตอบ
    (B)
    N and S
  • 40
    An inductor of inductance 10H carries a current of 0.2A. Calculate the energy stored in the inductor
    คำตอบ
    (B)
    0.2J
  • 41
    calculate the inductance of an inductor whose reactance is one ohm at 50 Hz.
    คำตอบ
    (C)
    3.18 x 10-3H
  • 42
    Borh's theory provides evidence for the
    คำตอบ
    (C)
    existence of energy level in the atom
  • 43
    A nuclide \(^{202}_{84} Y\) emits in succession an \(\alpha-particle\) and a \(\beta-particle\). The atomic number of the resulting nuclide is
    คำตอบ
    (B)
    83
  • 44
    The half life of a radioactive substance is 14 days. If 48g of this substance is stored, after how many days will 1.5g of the original substance remain?
    คำตอบ
    (B)
    70 days
  • 45
    A material of mass 1.0 x 10-2kg undergoes a fission process which decreases its mass by 0.02 percent. Calculate the amount of energy released in the process. (c = 3.0 x 108ms-1)
    คำตอบ
    (C)
    1.8 x 1011J
  • 46
    Absorption line spectra exhibited by atoms is a result of
    คำตอบ
    (C)
    excitation of an electron in the atom
  • 47
    In which of the following transitions is the largest quantum of energy liberated by an hydrogen atom when the electron changes energy levels? [n is the quantum number]
    คำตอบ
    (A)
    n = 2 to n = 1
  • 48
    A proton of wavelength \(\lambda_o\) is emitted when an electron in an atom makes a transition from a level of energy 2E. If the electron transits from \(\frac{4}{3}E_k\) to E level, determine the wavelength of the photon that would be emitted
    คำตอบ
    (A)
    3\(\lambda_o\)
  • 49
    The nucleon number and the proton number of a neutral atom of an element are 23 and 11 respectively. How many neutrons are present in the atom?
    คำตอบ
    (B)
    12
  • 50
    In a nuclear reactor, electricity can be generated through the following processes. Arrange the processes in the correct order. i. The steam is used to drive turbines. ii. The heat energy released is removed by passing water through the reactor. iii. The turbines in turn generate electricity. iv. The water then passes through some form of heat exchanger to produce steam
    คำตอบ
    (A)
    ii, iv, i and iii