WAEC - Physics (2006)

• 1

  Which of the following phenomena causes capillary of liquids in tubes of narrow bore?

  回答

  (B)

  surface tension
• 2

  Which of the following physical quantities are derived? i. Area ii. Thrust iii. Pressure iv. Mass

  回答

  (B)

  i, ii and iii only
• 3

  A block of volume 3 x 10⁵m³ and density 2.5 x 10³ kg m^-3 is suspended from a spring balance with \(\frac{2}{3}\) of its volume immersed in a liquid of density 900 kg m^-3. Determine the reading of the spring balance [g = 10ms^-2]

  回答

  (B)

  0.57N
• 4

  A solid body will float in a liquid if its

  回答

  (A)

  density is less than that of a liquid
• 5

  An object is said to undergo oscillatory motion when it moves

  回答

  (B)

  to and fro about a fixed point
• 6

  A body is rotating in a horizontal circle of radius 2.5m with an angular speed of 5 rad s-1. Calculate the magnitude of the radial acceleration of the body

  回答

  (C)

  12.50ms^-2
• 7

  A moving car of mass 800 kg experiences a frictional force of 200N. If it accelerates 2 ms^-2, calculate the magnitude of the force applied to the car

  回答

  (D)

  1800N
• 8

  Uniform speed occurs when there is equal change of

  回答

  (A)

  distance in equal times
• 9

  A car accelerates uniformly from rest at 5 ms^-2. Determine its speed after 10s

  回答

  (A)

  50.0ms^-1
• 10

  Which of the following quantities is a vector?

  回答

  (D)

  momentum
• 11

  which of the following statements about simple harmonic motion is correct? The

  回答

  (A)

  total mechanical energy is always conserved
• 12

  A force acting on a body causes a change in the momentum of a body from 12 kg ms^-1 to 16kg ms^-1 in 0.25. Calculate the magnitude of the impulse

  回答

  (C)

  4.0Ns
• 13

  Which of the following source of energy is renewable?

  回答

  (C)

  hydro
• 14

  A stone of mass 2.0kg is thrown vertically upward with a velocity of 20.0 ms^-1, calculate the initial kinetic energy of the stone

  回答

  (B)

  400J
• 15

  Which of the following statements about the mouth piece of a telephone is correct? It converts sound energy into

  回答

  (C)

  electrical energy
• 16

  The potential energy in an elastic string of force constant K which has been extended by X metres is expresses as

  回答

  (A)

  \(\frac{1}{2}k \Box ^2\)
• 17

  The engine of a train produces a force of 3000N when moving at 30.ms^-1. calculate the power of the engine

  回答

  (C)

  9.00 x 10⁴W
• 18

  The velocity ratio of an inclined plane, inclines at an angle \(\theta\) to the horizontal can be expressed as

  回答

  (A)

  (sin \(\theta)^{-1}\)
• 19

  A block and tackle system has six pulleys. a force of 50N applied to it lifts a load of weight W. If the efficiency of the system is 40%, calculate W

  回答

  (D)

  120N
• 20

  The sagging of overhead electrical cables is the consequence of

  回答

  (A)

  linear expansivity
• 21

  The silvered surface in a vacuum flask reduces heat loos due to

  回答

  (C)

  radiation
• 22

  How long will it take to heat 3kg of water from 28^oC to 88^oC in an electric kettle taking 6a from a 220V supply? [specific heat capacity of water = 4180 J kg^-1K^-1]

  回答

  (B)

  570s
• 23

  The amount of energy required to change a kilogram of ice in water without a change in temperature is

  回答

  (D)

  specific latent heat of fusion of ice
• 24

  A quantity of steam at 100^oC condenses to water at the same temperature by releasing 6.9 x 10⁴J of energy. Calculate the mass of the condensed steam. [specific latent heat of vaporization of eater = 2.3 x 10⁶ J kg^-1]

  回答

  (B)

  3.0 x 10^-2 kg
• 25

  The temperature of a liquid falls after some of it has evaporated because

  回答

  (B)

  the more energetic molecules have escaped into the atmosphere
• 26

  The S.I units of frequency, period and amplitude of a wave are respectively

  回答

  (D)

  hertz, second and metre
• 27

  a note of frequency 2000Hz has a velocity of 400 ms^-1. calculate the wavelength of the note

  回答

  (D)

  0.2m
• 28

  The eclipse of the moon occurs when the

  回答

  (B)

  earth comes exactly between the moon and the sun
• 29

  Which of the following observations cannot be explained using the rectilinear propagation of light?

  回答

  (D)

  diffraction patterns of light
• 30

  The distance between the successive crests of a wave travelling at 20ms\(^{-1}\) is 25cm. Calculate the frequency of the wave

  回答

  (D)

  80.0hz
• 31

  A ray from a fixed object is incident on a plane mirror at an angle of 20^o. If the mirror is rotated through 30^o by how many degree would the reflected ray rotate?

  回答

  (A)

  60^o
• 32

  Which of the following distances is usually adjustable in the camera? The distance between the

  回答

  (A)

  lens and the film
• 33

  A travelling microscope is focused on a mark on a table. If a glass block of thickness 18.0cm is placed on the mark by how many centimeters will the microscope be moved upwards so as to focus the mark once again? [refractive index of glass = 1.5]

  回答

  (D)

  6cm
• 34

  In which of the following media would sound wave travel fastest?

  回答

  (C)

  iron
• 35

  Which of the following actions is necessary in order to tune a string to produce a note of an octave higher than its fundamental?

  回答

  (B)

  reducing the tension by half
• 36

  The acceleration due o gravity may be defined as the force

  回答

  (C)

  with which the earth attracts one kilo-gram mass
• 37

  An electron of mass m and charge \(\Box\) enters a uniform electric field between two metal plates P and q separated by a distance d. P is maintained at a potential V while Q is earthed. Determine an expression for the magnitude of the acceleration of electron through the field

  回答

  (A)

  \(\frac{eV}{md}\)
• 38

  Which of the following factors does not affect the capacitance of a parallel plate capacitor?

  回答

  (B)

  nature of the surface of the plates
• 39

  The equivalent capacitance of a 3\(\mu F\) capacitor and a 6\(\mu F\) capacitor connected in parallel is

  回答

  (D)

  9.0\(\mu F\)
• 40

  a cell of e.m.f. 1.5V and internal resistance 1.0\(\Omega\) is connected to two resistor of resistance 2.0\(\Omega\) and 3.0\(\Omega\) in series. Calculate the current through the resistors

  回答

  (A)

  0.25A
• 41

  An electric lamp rated 120W is used on a 240Vrms, calculate the resistance of its filament

  回答

  (A)

  480\(\Omega\)
• 42

  Which of the following statements about a bar magnet is correct?

  回答

  (D)

  the magnetic properties are more pronounced at points near the end of the bar
• 43

  The force experienced by a current-carrying conductor move in a magnetic field is employed in the working of the i. moving coil ammeter ii. electric bell iii. electric motor. Which of the statements above are correct?

  回答

  (C)

  i and iii only
• 44

  The breaking up of an atomic nucleus into the fragment of nearly equal size is known as

  回答

  (B)

  nuclear fission
• 45

  A 500kV is applied across an X-ray tube. Calculate the maximum velocity of the electrons produced [Me = 9.1 x 10^-31kg, e = 1.6 x 10^-19C]

  回答

  (A)

  4.2 x 10⁸ms^-1