WAEC - Physics (2014)

  • 1
    A ball falling through a viscous liquid is acted upon by
    Odpowiedź
    (D)
    upthrust, the ball's weight and viscous force
  • 2
    An object of mass m moves with a uniform speed v round a circular path of radius r. If its angular speed is \(\omega\), the magnitude of the centripetal force acting on it is
    Odpowiedź
    (A)
    \(m \omega^2 r\)
  • 3
    When an elastic material is stretched by a force, the energy stored in it is
    Odpowiedź
    (B)
    potential
  • 4
    When the linear momentum of a body is constant, the net force acting on it
    Odpowiedź
    (A)
    is zero
  • 5
    If no net force acts on an object, the object maintains a state of rest or constant speed in a straight line. The above is a statement of Newton's
    Odpowiedź
    (A)
    first law of motion
  • 6
    Which of the following pairs of physical quantities is made up of vectors?
    Odpowiedź
    (C)
    dislacement and acceleration
  • 7
    The knowledge of surface tension is applied in the following areas except in
    Odpowiedź
    (B)
    production of palm oil
  • 8
    A body is projected vertically upwards with a speed of 10 ms-1 from a point 2m above the ground. Calculate the total time taken for the body to reach the ground. [g = 10ms-2]
    Odpowiedź
    (B)
    2.00s
  • 9
    A car starts from rest and covers a distance of 40m in 10s. Calculate the magnitude of its acceleration
    Odpowiedź
    (B)
    0.80ms-2
  • 10
    The diagram above illustrates a uniform metre rule which is balanced on a pivot by some masses. Calculate the value of M
    Odpowiedź
    (D)
    25.0g
  • 11
    The period of a simple pendulum X is 5s. What is the period of a simple pendulum Y which makes 50 vibrations in the same time it takes X to make 20 vibrations?
    Odpowiedź
    (C)
    2.0s
  • 12
    Alcohol of mass 21g and density 0.7g cm-3 is mixed with 10g of water. Determine the density of the mixture [density of water = 1.0gcm-3]
    Odpowiedź
    (A)
    0.775gcm-3
  • 13
    A device that converts mechanical energy into electrical energy is
    Odpowiedź
    (A)
    a dynamo
  • 14
    The S.I unit of power is
    Odpowiedź
    (C)
    W
  • 15
    A screw-jack has the distance between its successive threads as P and the length of its tommy bar as r. Its velocity ratio is given by the expression
    Odpowiedź
    (B)
    \(\frac{2 \pi r}{P}\)
  • 16
    Heat transfer by conduction is similar to wave motion because
    Odpowiedź
    (D)
    no transfer of materials is involved
  • 17
    The temperature at which the water vapor in the air saturates the air and begins to condense is known as
    Odpowiedź
    (A)
    dew point
  • 18
    The change of state from solid to liquid occurs
    Odpowiedź
    (A)
    at constant temperature
  • 19
    Which of the following types of thermometers can be used to measure a range of temperature from -50°C to 50°? i. Clinical ii. Mercury iii. Alcohol-in-glass
    Odpowiedź
    (C)
    iii only
  • 20
    A body of mass M kg rests on a plane inclined at an angle \(\theta\) to the horizontal. The component of the weight of the body parallel to the plane is
    Odpowiedź
    (A)
    Mg sin \(\theta\)
  • 21
    A quantity of water at 20oC is mixed with another quantity of water at 70oC. The final steady temperature of the mixture is 40oC. Determine the ratio of the mass of the cold water to that of the hot water
    Odpowiedź
    (B)
    3:2
  • 22
    The mass of an empty density bottle is 30g. When filled with a liquid, the mass of the bottle and the liquid is 40g. On heating the filled bottle through 40ºc, the mass reduces to 38g. Calculate the apparent cubic expansivity of the liquid
    Odpowiedź
    (B)
    6.25 x 10-3K-1
  • 23
    A car traveling at 30ms\(^{-1}\) overcomes a frictional resistance of 100N while moving. Calculate the power developed by the engine. [1 hp = 0.75 kW]
    Odpowiedź
    (C)
    4.00hp
  • 24
    The quality of a note depends on its
    Odpowiedź
    (C)
    overtones
  • 25
    A transverse wave can be distinguished from a longitudinal wave by
    Odpowiedź
    (D)
    polarization
  • 26
    Refraction of lights differs from reflection in that, in refraction i. at least two media are involved ii. there is a change in the direction of the ray iii. the speed of the ray changes. Which of the statements above is/are correct?
    Odpowiedź
    (D)
    i and iii only
  • 27
    Which of the following relations about the focal length fo of the objective and focal length fe of the eye piece of a compound is correct?
    Odpowiedź
    (B)
    fo < fe
  • 28
    The functional difference between a lens and a mirror is that a lens
    Odpowiedź
    (B)
    refracts a beam of light while a mirror reflects it
  • 29
    The diagram above illustrates an electromagnetic wave travelling with speed 3.0 x 108ms-1. Calculate the wave length of the wave
    Odpowiedź
    (C)
    0.16m
  • 30
    A fish inside a pond appears to be at a depth of 1.5m when viewed vertically from above. The refractive index of the water in the pound is 1.3. Calculate the apparent displacement of the fish
    Odpowiedź
    (D)
    0.45m
  • 31
    an observer hears an echo 1.26 seconds after blowing a whistle near a cliff. calculate the distance of the observer from the cliff. [speed of sound in air = 330ms-1]
    Odpowiedź
    (B)
    207.9m
  • 32
    An object is placed in front of two plane mirrors inclined at 60o to each other. Determine the number of the images formed
    Odpowiedź
    (C)
    5
  • 33
    An ammeter can be adapted to measure potential difference by using a
    Odpowiedź
    (B)
    multiplier
  • 34
    The region around a magnet in which magnetic force can be expressed is known as
    Odpowiedź
    (C)
    field
  • 35
    In an ac circuit when the supply voltage frequency is equal to the resonant frequency, the current
    Odpowiedź
    (D)
    is in phase with the supply voltage
  • 36
    The energy stored in a simple cell is
    Odpowiedź
    (D)
    chemical
  • 37
    Which of the following conditions occur at resonance in a series RLC circuit? i. Impedance equals resistance ii. Current is maximum iii. Reactance is maximum iv. Current and voltage are 90° out of phase
    Odpowiedź
    (A)
    i and ii only
  • 38
    An electric motor converts
    Odpowiedź
    (A)
    electrical energy to mechanical energy
  • 39
    A 15 \(\mu F\) capacitor is connected to a 240V, 50Hz ac. source. Calculate the reactance of the capacitance [\(\pi = 3.142\)]
    Odpowiedź
    (D)
    212\(\Omega\)
  • 40
    Two identical charges situated 20cm apart in vacuum repel each other with a force of 1.0N.Calculate the value of each other with a force of 1.0N. Calculate the value of each charge. [(14 \(\pi \varepsilon_o)^{-1}\) = 9 x 109Nm2C-2]
    Odpowiedź
    (A)
    21\(\mu C\)
  • 41
    In the circuit diagram above, E is a battery of negligible internal resistance. If its emf is 9.0V. Calculate the current in the circuit ``
    Odpowiedź
    (B)
    1.0A
  • 42
    A wire of length 100 cm has a resistance of 10\(\Omega\). If its cross-sectional area is 0.005cm2, determine its resistivity
    Odpowiedź
    (A)
    0.0005\(\Omega\)cm
  • 43
    A transformer has 400 turns of wire in the primary coil and 40 turns in the secondary col. If the input voltage is 150 volts. Calculate the magnitude of the output voltage
    Odpowiedź
    (D)
    15V
  • 44
    The circuit above illustrates a standard resistor R, voltage source E and a lamp L connected in series. If the temperature of R is increased, the brightness of the lamp will
    Odpowiedź
    (B)
    decrease slightly
  • 45
    The energy required to separate the nucleus in an atom completely is known as
    Odpowiedź
    (D)
    nuclear binding energy