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JAMB - Physics (2012)

  • 1
    In order to remove the error of parallax when taking measurements with a metre rule, the eye should be focused
    คำตอบ
    (C)
    vertically downwards on the markings
  • 2
    A load is pulled at a uniform speed along a horizontal floor by a rope at 45o to floor. If the force in the rope is 1500N, what is the frictional force on the load ?
    คำตอบ
    (D)
    1061N
  • 3
    Calculate the total distance covered by a train before coming to rest if its initial speed is 30ms-1 with a constant retardation of 0.1m-2
    คำตอบ
    (B)
    4500m
  • 4
    A car starts from rest and moves with a uniform acceleration of 30ms-2 for 20s. Calculate the distance covered at the end of the motion
    คำตอบ
    (A)
    6km
  • 5
    A rocket is fired from the earth's surface to a distant planet. By Newton's law of universal gravitation, the force F will
    คำตอบ
    (A)
    increase as r reduces
  • 6
    If a freely suspended object is pulled to one side and released, it oscillates about the point of suspension because the
    คำตอบ
    (A)
    acceleration is directly proportional to the displacement
  • 7
    An object moves in a circular path of radius 0.5m with a speed of 1ms-1 What is its angular velocity?
    คำตอบ
    (C)
    2 rads-1
  • 8
    An object of mass 20kg slides down an inclined plane at an angle of 30o to the horizontal. The coefficient of static friction is?
    [g = 10ms-2]
    คำตอบ
    (D)
    0.6
  • 9
    A block and tackle is used to raise a load of 250N through a vertical distance of 30m. What is the efficiency of the system if the work done against friction is 1500J?
    คำตอบ
    (C)
    83.3%
  • 10
    If a load of 1 kg stretches a cord by 1.2cm, what is the force constant of the cord? {g=10ms-2}
    คำตอบ
    (B)
    833Nm-1
  • 11
    An object of volume 1 m 3 and mass 2kg is totally immersed in a liquid of density 1 kgm-3 . Calculate its apparent weight.
    คำตอบ
    (B)
    10N
  • 12
    The pressure at any point in a liquid at rest depends only on the
    คำตอบ
    (A)
    depth and the density
  • 13
    A balloon whose volume is 300m3 is filled with hydrogen. If the density of air is 1.3 kgm-3, find the upthrust on the balloon. [g = 10ms-2]
    คำตอบ
    (C)
    3900N
  • 14
    Clinical thermometers are examples of
    คำตอบ
    (D)
    mercury- in - glass thermometer
  • 15
    Two metals P and Q are heated through the same temperature difference. If the ratio of the linear expansivities of P to Q is 2:3 and the ratio of their
    length is 3: 4 respectively, the ratio of the increase in lengths of P to Q is
    คำตอบ
    (A)
    1:2
  • 16
    2000cm3 of a gas is collected at 27oC and 700mmHg. What is the volume of the gas at standard temperature and pressure?
    คำตอบ
    (C)
    1676.3cm3
  • 17

    Calculate the temperature change when 500J of heat is supplied to 100g of water

    [specific heat capacity of water = 4200JKg\(^{-1}\)k\(^{-1}\)]

    คำตอบ
    (C)
    1.2oC
  • 18
    Which of the following is NOT a factor that can increase the rate of evaporation of water in a lake?
    คำตอบ
    (A)
    increase in the pressure of the atmosphere
  • 19
    The quantity of heat energy required to melt completely 1 kg of ice at - 30oC is
    [latent heat of fusion = 3.5 x 10 5Jkg -1, specific heat capacity of ice = 2.1x10 3Jkg -1K -1]
    คำตอบ
    (B)
    4.13x10 5J
  • 20
    I. It is a rapid, constant and irregular motion of tiny particles. II. It gives evidence that tiny particles of matter called molecules exist. III. It takes place only in gases. IV. It gives evidence that molecules are in a constant state of random motion. which of the combinations above is correct about Brownian notion?
    คำตอบ
    (D)
    l, ll and lV only
  • 21
    The equation of a wave traveling in a horizontal direction is expressed as y = 15 sin \(\frac{2\pi}{5}\) (60t - x). What is its wavelength?
    คำตอบ
    (C)
    5m
  • 22
    Which of the following factors will affect the velocity of sound?
    คำตอบ
    (C)
    Wind travelling in the same direction of the sound
  • 23
    The characteristic of a vibration that determines its intensity is the
    คำตอบ
    (D)
    Amplitude
  • 24
    Where can a man place his face to get an enlarged image when using a concave mirror to shave?
    คำตอบ
    (C)
    Between the principal focus and the pole
  • 25
    A pinhole camera is placed 300m in front of a building so that the image is formed on a screen 5cm from the the pinhole. If the image is 2.5cm high, the height of the building will be
    คำตอบ
    (D)
    150m
  • 26
    The magnification of an object 2cm tall when placed 10cm in front of a plane mirror is
    คำตอบ
    (B)
    1.0
  • 27
    After reflection from the concave mirror, rays of light from the sun converges
    คำตอบ
    (B)
    at the focus
  • 28
    A glass block of thickness 10cm is placed on an object. If an observer views the object vertically, the displacement of the object is
    คำตอบ
    (A)
    3.33cm
  • 29
    I. Rays of light travel from a less dense medium to a denser medium. II. The Angle of incidence is greater than critical angle. III. Rays of light travel from a denser medium to a less dense medium. Which of the statements above are conditions for total internal reflection to occur?
    คำตอบ
    (C)
    II & III only
  • 30
    The use of lenses is Not applicable in the
    คำตอบ
    (C)
    periscope
  • 31
    Disperson of white light is the ability of white light to
    คำตอบ
    (D)
    separate to its component colours
  • 32
    A newly charged 12V accumulator can easily start a car whereas eight new dry cells in series with a effective e.m.f. of 12V cannot start the same car because
    คำตอบ
    (B)
    The current capacity is low
  • 33
    The fuse in an electric device is always connected to the
    คำตอบ
    (C)
    live side of an electric supply
  • 34
    A particle carrying a charge of 1. 0 x 10-8C enters a magnetic field at 3.0x 10-2 ms -1 at right angles to the field. If the force on this particle is 1.8 x 10-8N, what is the magnitude of the field?
    คำตอบ
    (B)
    6.0x10T
  • 35
    The current output from of an a.c. source is given as I = 10 sin to t. The d.c equivalent of the current is
    คำตอบ
    (B)
    7.1A
  • 36
    A conductor of length 1m moves with a velocity of 50ms-1 at an angle of 30o to the direction of a uniform magnetic field of flux density 1.5Wbm-2. What is the e.m.f induced in the conductor?
    คำตอบ
    (A)
    37.5V
  • 37
    The process of detecting a pin mistakenly swallowed by a child is X-ray
    คำตอบ
    (A)
    Diagnosis
  • 38
    Which of the following CANNOT be deflected by both electric and magnetic fields?
    คำตอบ
    (A)
    Gamma rays
  • 39
    A piece of radioactive material contains 1000 atmos. If its half -life is 20seconds, the time taken for 125 atoms to remain is
    คำตอบ
    (D)
    60 seconds
  • 40
    The p-n junction diodes can act as rectifiers because they
    คำตอบ
    (A)
    conduct current when forward-biased