WAEC - Physics (2010)

• 1

  Which of the following properties of a long steel bar would alter if the bar were melted, recast into a cube and allowed to cool to its original temperature?

  回答

  (B)

  volume
• 2

  Which of the following instruments is best for measuring the diameter of a thin constantan wire?

  回答

  (C)

  micometer screw guage
• 3

  What is the density of a fuel of relative density 0.72? [Density of water = 1000kg m^-3]

  回答

  (B)

  720 kgm^-3
• 4

  The types of motion which a cylindrical drum rolling down an inclined plane undergoes are

  回答

  (B)

  rotational and translational
• 5

  Which of the following statements about static friction is correct? It

  回答

  (C)

  depends on the relative motion between the surface in contact
• 6

  Which of the following statements about moving particle is correct?

  回答

  (A)

  if the resultant force acting on the particle is zero, then it is in dynamic equillibrium
• 7

  Two cars X and Y travelling in opposite directions along the same high way at uniform velocities 110 kmh^-1 and 90kmh^-1 respectively pass each other at a certain point. The velocity of X relative to Y at the time they pass each other is

  回答

  (A)

  200 kmh^-1
• 8

  The average speed of an object is determined by dividing the sum of its initial and final speeds by two only when the acceleration is

  回答

  (B)

  uniform
• 9

  a body is projected horizonatlly from the top of a cliff 45m above the ground. if the body lands at a distance 30m from the foot of the cliff, calculate the speed of projection. [g = 10ms-2]

  回答

  (A)

  10ms^-1
• 10

  Which of the following statements best describes a rigid body? A body which

  回答

  (A)

  is not equally deformed
• 11

  simple harmonic oscillator has a period of 0.02s and amplitude of 0.25m. Calculate the speed in ms^-1 at the centre of the oscillation

  回答

  (B)

  25.00\(\pi\)
• 12

  A vertical string, suspended from a fixed point and having a small mass attached to the free end is set into oscillations. Which of the following statements about the system are correct? i. The potential energy of the mass is a minimum at the middle of the swing ii. Its kinetic energy is a maximum at the middle of the swing iii. The sum of the potential and kinetic energies is constant throughout the swing

  回答

  (C)

  ii and iii only
• 13

  A moving body of mass 25.0kg undergoes a uniform retardation of 20.0ms^-2. Calculate the magnitude of the retardating force

  回答

  (D)

  500.00N
• 14

  Which of the following sources of energy is/are exhausible? i. Solar ii. Fossil fuels iii. Tidal power

  回答

  (D)

  ii only
• 15

  a machine is said to be a third class lever when the

  回答

  (C)

  effort is between the fulcrum and load
• 16

  a thermometer records 680 mmHg at steam point and 440 mmHg at ice point. The temperature it records at 380 mmHg is

  回答

  (A)

  -25^oC
• 17

  The advantages of the thermoelectric thermometer include the following characteristics except that it

  回答

  (D)

  is fairly sensitive
• 18

  In a thermos flask, heat loss by radiation is minimizes by the

  回答

  (A)

  silvered surfaces
• 19

  The pressure P, volume V, and absolute temperature T of a given mass of an ideal gas change simultaneously. Which of the followng equations is correct about the gas?

  回答

  (D)

  \(\frac{I}{T} = \frac{constant}{PV}\)
• 20

  Specific heat capacity 36.4 Jkg-1 K-1 of a body means that when 36.4J of heat energy is supplied to a body of

  回答

  (C)

  mass 1kg, the temperature rises by 1K
• 21

  An electric drill rated 400W is used to drill a hole in copper of mass 400g in 20s. Calculate the rise in temperature if all the heat produced is absorbed by the copper. [specific heat capacity of copper = 400Jkg^-1K^-1]

  回答

  (C)

  50^oC
• 22

  A solid of mass 0.5kg initially at 50^oC melts at 60^oC. Calculate the quantity of heat required to melt it completely. [specific heat capacity of the solid =2.0KJ kg^-1K^-1][Specific latent heat of fusion of solid =1.0 KJ kg^-1]

  回答

  (C)

  10500J
• 23

  Dew point is not affected by

  回答

  (B)

  wind
• 24

  A certain wave has a speed of 20ms^-1. If the frequency of the wave is 0.25Hz, calculate the distance between successive crests of the wave

  回答

  (D)

  80.0m
• 25

  The ability of a wave to spread around corners is called

  回答

  (C)

  diffraction
• 26

  The following devices use plane mirrors in their operations, except

  回答

  (D)

  binoculars
• 27

  When an object is placed at the principal focus of a concave mirror, the location of the image formed is

  回答

  (C)

  at infinity
• 28

  

  From the diagram, the correct equation for the refractive index n of the medium is

  回答

  (A)

  n = tan i
• 29

  A ray of light travels from air to water. The refeactive index of water is given by the expression

  回答

  (D)

  \(\frac{\text{wavelength in air}}{\text{wavelength in water}}\)
• 30

  A lens that is thinner at the middle and thicher at the edges is

  回答

  (A)

  diverging
• 31

  Which of the following electromagnetic wave has the longest wavelength?

  回答

  (A)

  radio-waves
• 32

  The amplitude of a sound wave determines its

  回答

  (C)

  loudness
• 33

  As the air column of length L in an air pipe decreases, the frequency of the sationary wave emitted

  回答

  (A)

  decreases
• 34

  A positively charged glass rod is placed near the cap of a positively charged electroscope. The divergence of the leaf is observed to

  回答

  (B)

  increase
• 35

  Capacitors are used in the following devices, except

  回答

  (C)

  electric irons
• 36

  

  Use the diagram above to calculate the current, I.

  回答

  (B)

  0.97A
• 37

  

  Determine the potential difference. V across the parallel resistors

  回答

  (B)

  2.3V
• 38

  A galvanometer of internal resistance 50\(\Omega\) and full scale deflection of 20 mA is converted into a voltmeter by connecting a resistor of resistance 1950\(\Omega\) in series to it. Calculate the maximum voltage that can be read by the voltmeter

  回答

  (D)

  40V
• 39

  In the wiring of houses, the fuse is connected to the wire coloured

  回答

  (B)

  brown
• 40

  Which of the following factors does not affect the electric resistance of wire?

  回答

  (B)

  mass
• 41

  Which of the following factors will increase the sensitivity of moving coil meter?

  回答

  (D)

  soft iron core
• 42

  In order to prevent bar magnets from losing their strength, they are stored wih keepers such that the two bars are placed with

  回答

  (C)

  unlike poles facing each other and the keepers placed at their ends
• 43

  The energy, E stored in an inductor of inductance L when current I passes through it is given by the equation

  回答

  (B)

  E = LI²
• 44

  The resonant frequency of an a.c circuit is 1000 kHz. If each of the capacitance and inductance in the circuit is reduced by 50%, and no other changes are made, the resonant frequency will become

  回答

  (D)

  2000kHz
• 45

  Eddy currents can be reduced by

  回答

  (C)

  creating holes in the metal plates