JAMB - Physics (1992)

  • 1
    What is the least possible error in using a rule graduated in centimeters?
    Răspuns
    (A)
    0.1cm
  • 2
    Which of the following affects the period of a simple pendulum? i. mass of the pendulum bob. ii. length of the pendulum. iii. acceleration due to gravity.
    Răspuns
    (B)
    ii and iii only
  • 3
    A boy sits in a train moving with uniform speed on a straight track. If from his outstretched palm he gently tosses his coin upwards, the coin will fall
    Răspuns
    (D)
    into his palm
  • 4
    A body starts from rest and moves with a uniform acceleration of 6 ms \(^{-2}\). What distance does it cover in the third seconds
    Răspuns
    (A)
    15m
  • 5
    A stone, Q is thrown with velocity U at an angle of 75o to the horizontal. Another stone R is thrown with the same velocity U but with an angle of 15o to the horizontal. The ranges covered by the stones will be
    Răspuns
    (C)
    the same for Q and R
  • 6
    A man weight 800N climbs up a stairs to height of 15m in 12.5s. What is the man''s average power output?
    Răspuns
    (C)
    960W
  • 7
    A machine requires 1000J of work to raise a load of 500N through a vertical distance of 1.5m. Calculate the efficiency of the
    Răspuns
    (B)
    75%
  • 8
    In an experiment to determine Young's Modulus for a wire, several loads are attached to the wire and the corresponding extension measured. The tensile stress in each case depends on the
    Răspuns
    (B)
    load and the radius of the wire
  • 9
    If a plastic sphere floats in water (density = 1000kgm3) with 0.5 of its volume submerged, and floats in oil with 0.4 of its volume submerged the density of the oil is
    Răspuns
    (C)
    1250kgm3
  • 10
    A platinum resistance thermometer wire has a resistance of 5 ohms at 0oC and 5.5 ohms at 100oC. Calculate the temperature of the wire when the resistance is 5.2 ohms
    Răspuns
    (C)
    40oC
  • 11
    A bridge made of steel is 600m long. What is the daily variation in its length if the night-time and daytime temperatures are 10°C and 35°C respectively. The linear expansivity of steel is 0.000012C\(^{-1}\).
    Răspuns
    (C)
    18.00cm
  • 12
    One of the most important applications of bi-metallic strip is found in the construction of
    Răspuns
    (A)
    a thermostat
  • 13
    At constant pressure, the density of a fixed mass of gas is
    Răspuns
    (C)
    inversely proportional to its temperature
  • 14
    How much heat is absorbed when a block of copper of mass 0.05kg and specific heat capacity 390Jkg-1K-1 is heated from 20oC to 70oC?
    Răspuns
    (B)
    9.75 x 102J
  • 15
    A block of ice floats on water inside a container. If the block of ice gets completely melted, the level of water in the container will
    Răspuns
    (B)
    remain the same
  • 16
    The space between the double glass walls of a thermos flask is evacuated space are silvered. The residual source of heat loss takes place by
    Răspuns
    (C)
    conduction through the stopper and the glass
  • 17
    The equation of a wave is y = 0.005 sin[x(0.5X - 200t)] where x and y are in meters and t is in seconds. What is the velocity of the wave?
    Răspuns
    (B)
    400ms-1
  • 18
    Which of the following characteristics of a wave is used in the measurement of the depth of the sea?
    Răspuns
    (D)
    reflection
  • 19
    A note is the octave of another note if it has
    Răspuns
    (A)
    a frequency twice that of the first note
  • 20
    What is the frequency of the sound made by a siren having a disc with 32 holes and making 25 revolution per seconds?
    Răspuns
    (C)
    800Hz
  • 21
    Which of the following properties make the convex mirror useful as a driving mirror? i. the image is real. ii. the image is erect. iii. it has a wide field of view. iv. the image is magnified.
    Răspuns
    (C)
    ii and iii
  • 22
    When an object is placed very close to the pole of a concave mirror, the virtual image obtained is
    Răspuns
    (D)
    enlarged and upright
  • 23
    A concave mirror has a radius of curvature of 36cm. At what distance from the mirror should an object be placed to give a real image three times the size of the object?
    Răspuns
    (B)
    24cm
  • 24
    Which of the following statements is CORRECT about a long-sighted boy who does not put on glasses?
    Răspuns
    (D)
    Parallel rays of light are focused behind his retina
  • 25
    The speed of light in air is 3 x 10\(^8\)ms\(^{-1}\). What is the speed in glass with a refractive index of 1.50?
    Răspuns
    (C)
    2.0 x 108ms-1
  • 26
    If the refractive index of a medium in air is 2.0, what is the critical angle for this medium?
    Răspuns
    (A)
    30o
  • 27
    Which of the following arrangements of the components of electromagnetic spectrum is in ascending order of wavelengths?
    Răspuns
    (B)
    Gamma rays, X-rays, ultraviolet rays, infra-red rays
  • 28
    The angle between the direction of the earth's magnetic field and the horizontal is called the
    Răspuns
    (D)
    angle of dip
  • 29
    Calculate the force acting on an electron of charge 1.6 x 10-19C placed in an electric field of intensity 108Vm-1
    Răspuns
    (A)
    1.6 x 10-11N
  • 30
    When an ebolite rod is rubbed with fur, it has
    Răspuns
    (B)
    a negative charge
  • 31
    Which of the following factors has no effect on the e.m.f. of a primary cell?
    Răspuns
    (B)
    size of the cell
  • 32
    A wire of length 15m made of a material of resistivity 1.8 x 10-6\(\Omega\)m has a resistance of 0.27\(\Omega\). Determine the area of the wire
    Răspuns
    (B)
    1.0 x 10-4m2
  • 33
    A 5-v battery is connected across the plates of a 2.0\(\mu\)F uncharged parallel plate capacitor. The charge on the capacitor after a long time is
    Răspuns
    (B)
    10.0\(\mu\)C
  • 34
    Which of the following apparatus will require the smallest fuse rating for its protection?
    Răspuns
    (A)
    60W, 240V
  • 35
    The heat produced in a conductor carrying an electric current is
    Răspuns
    (D)
    directly proportional to the square of the current, the resistance and the time
  • 36
    The maximum permissible current through a galvanometer G of internal resistance 10\(\Omega\) is 0.05A. A resistance R is used to convert G into a voltmeter with a maximum reading of 100V. Find the value of R and how it is connected to G
    Răspuns
    (C)
    1990 ohms in series
  • 37
    In alternating current theory, the units of impedance, r.m.s. voltage and resonance frequency are respectively equal to
    Răspuns
    (B)
    ohms, volt and hertz
  • 38
    In A.C circuit theory, the root means square (r.m.s) current, Irms and the peak (maximum)current Io are related by
    Răspuns
    (B)
    Irms = \(\frac{I_o}{\sqrt{2}}\)
  • 39
    The threshold of frequency for photoelectric effect depends on the
    Răspuns
    (C)
    material of the photocathode
  • 40
    After three half lifes, the fraction of a radioactive material that has decayed is
    Răspuns
    (D)
    \(\frac{7}{8}\)
  • 41
    \(^{27}_{13}Al\) + \(^{1}_{0}n\) \(\Rightarrow\) \(^{24}_{11}Na\) + X
    Răspuns
    (D)
    an alpha particle
  • 42
    A uniform light rod is kept in horizontal equilibrium under the influence of fore forces as shown above, which of the following equations correctly represents the condition of equilibrium for the rod
    Răspuns
    (D)
    F1a + F2b - F3c - F4d = 0
  • 43

    In the diagram above, the hanging mass \(m_2\) is adjusted until \(m_1\) is on the verge of sliding. The coefficient of static friction between the mass \(m_1\) and the table is

    Răspuns
    (C)
    m2/m1
  • 44

    The fig above shows the heights of two liquids X and Y when some air is sucked out of the apparatus through the pump P. The diameter of the table in X is twice That of the Tube In Y. What is the relative density of the liquid X with respect to liquid Y

    Răspuns
    (C)
    3
  • 45
    The diagram above represents the field pattern obtained by bringing the poles of two magnets together.The poles must be
    Răspuns
    (A)
    S-S poles