JAMB - Physics (1985)

• 1

  Which of the following is NOT a fundamental S.I unit?

  回答

  (E)

  Radian
• 2

  A simple pendulum with a period of 2.0s has its length doubled. Its new period is

  回答

  (D)

  2.83s
• 3

  Which of the following statements are true about the spring balance and the chemical balance? i. both are used to measure the mass of an object. ii. either of them may be used to measure the weight of an object. iii. the spring balance works on the principle of Hooke's law while the chemical balance works on the principle of moments. iv. a change in gravity does the readings of a spring balance but not that of a chemical balance.

  回答

  (B)

  ii and iii
• 4

  Which of the following types of motion are oscillatory? i.a diving board when used by a diver. ii. the motion of the balance wheel of a wrist watch. iii. the motion of the turn-table of a record player. iv. the motion of the center of a ten kobo piece as it rolls down an inclined plane. v. the motion of the needle of a D.C. ammeter into which a low A.C. current is passed

  回答

  (D)

  i, ii and v
• 5

  If a car starts from rest and moves with a uniform acceleration of 10ms^-2 for ten seconds, the distance it covers in the last one second of its motion is

  回答

  (A)

  95m
• 6

  A block of mass 2.04kg resting on a smooth horizontal plane is acted upon simultaneously by two-forces, 10N due North and 10N due East. The magnitude of the acceleration produced by the force on the block is

  回答

  (B)

  7.07ms^-2
• 7

  A metal block of mass 5kg lies on a rough horizontal platform. If a horizontal force of 8N applied to the block through its center of mass just slides the block on the platform, then the coefficient of limiting friction between the block and platform is

  回答

  (A)

  0.16
• 8

  Which of the following is NOT a force?

  回答

  (E)

  Impulse
• 9

  Two masses 40g and 60g respectively, are attached firmly to the ends of the light meter rule. The center of gravity of the system is

  回答

  (C)

  40cm from the heavier mass
• 10

  A 0.05kg bullet travelling at 500ms^-1 horizontally strikes a thick vertical wall. It stops after penetrating through the wall horizontal distance of 0.25m. What is the magnitude of the average force the wall exerts on the bullet?

  回答

  (E)

  25 000N
• 11

  A force of 100N stretches an elastic string to a total length of 20cm. If an additional force of 100N stretches the string 5cm further, Find the natural length of the string

  回答

  (A)

  15cm
• 12

  Two divers G and H are at depths 20m and 40m respectively below the water surface in a lake. The pressure on G is P1 while the pressure on H is P2. If the atmospheric pressure is equivalent to 10m of water, then the value of \( \frac{p_2}{p_1} \) is?

  回答

  (C)

  1.67
• 13

  The areas of the effort and load pistons of a hydraulic press are 0.5m² and 5m² respectively. If a force F₁ of 100N is applied on the effort piston, the force F₂ on the load is

  回答

  (D)

  1000N
• 14

  A metal cube of volume 10³mm³ is lowered into a measuring cylinder containing water. If the internal cross-sectional area of the cylinder is 1.5 x 10²mm², by how much does the water level rise in the cylinder?

  回答

  (A)

  6.67 x 10⁰mm
• 15

  A uniform cylindrical block of wood floats in water with one-third of its height above the water level, in a liquid of relative density 0.8, what fraction of its height will be above the liquid level?

  回答

  (A)

  \(\frac{1}{6}\)
• 16

  A thin aluminum plate has a surface area of 1.500m at 20ºC. What will be its surface area when it is cooled to -20ºC? (Take the linear expansivity of aluminum to be 2.5 x 10-5k-1).

  回答

  (D)

  1.497m²
• 17

  Two liquids, P at a temperature of 20^oC and Q at a temperature of 80^oC have specific heat capacities of 1.0Jkg^-1oC^-1 and 1.5J kg^{-1 o}C^-1respectively. if equal masses of P and Q are mixed in a lagged calorimeter, then the equilibrium temperature is

  回答

  (C)

  56^oC
• 18

  A quantity of gas occupies a certain volume when the temperature is -73oC and the pressure is 1.5 atmospheres. If the pressure is increased to 4.5 atmospheres and the volume is halved at the same time, what will be the new temperature of the gas?

  回答

  (E)

  27^oC
• 19

  In a gas experiment, the pressure of the gas is plotted against the reciprocal of the volume of the gas at a constant temperature. the unit of the slope of the resulting curve is

  回答

  (C)

  work
• 20

  Water shows anomalous behaviour.

  回答

  (B)

  between 0^{oC and 4oC}
• 21

  Two thermo flasks of volume Vx and Vy are filled with liquid water at an initial temperature of 0^oC. After sometime the temperature were found to be 9x, 9y, respectively. Given that \(\frac{Vx}{Vy}\) = 2 and \(\frac{\theta x}{\theta y}\) = \(\frac{1}{2}\) the ratio of the heat flow into the flask is

  回答

  (D)

  1
• 22

  A good calorimeter should be of

  回答

  (D)

  high specific heat capacity and low heat conductivity
• 23

  Which of the following statements are NOT correct?

  回答

  (B)

  both the boiling point and the saturated vapour pressure of a given liquid depends on the external pressure
• 24

  Which of the following phenomena CANNOT be explained by the molecular theory of matter?

  回答

  (D)

  Radiation
• 25

  In order to find the depth of the sea, a ship sends out a sound wave and receives an echo after one second. If the velocity of sound in water is 1500ms^-1, what is the depth of the sea?

  回答

  (A)

  0.75km
• 26

  When a sound wave passes from air into water its

  回答

  (B)

  speed and wavelength increases but its frequency remains the same
• 27

  If the fundamental frequency of a closed pipe organ on a day when the speed of sound is 340ms^-1 is 170Hz, then the length of the pipe is

  回答

  (A)

  50cm
• 28

  An object is placed 15cm in front of a concave mirror of radius 40cm. The image formed

  回答

  (A)

  virtual and 60cm behind the mirror
• 29

  A 45^o triangular glass prism can be used as a reflector of light because

  回答

  (E)

  the critival angle angle for glass is less than 45^o
• 30

  A convex mirror is used as a driving mirror because i. its image is erect. ii. it has a large field of view. iii. it has a long focal length. Identify the CORRECT statement(s)

  回答

  (B)

  i and ii only
• 31

  Two rays of light from a point below the surface of water are equally inclined to each other at 60^o in water. What is the angle between the rays when they emerge into air? (Take the refractive index of water to be \(\frac{4}{3}\))

  回答

  (D)

  83.6^o
• 32

  A narrow beam of white light can be split up into different colours by a glass prism. The correct explanation is that

  回答

  (D)

  different colours of white light travel with different speeds in glass
• 33

  A charge of one coulomb liberates 0.0033g of copper in an electrolytic process. How long will it take a current of 2A to librate 1.98g of copper in such a process?

  回答

  (A)

  5 mins
• 34

  If the distance between two stationary charged particle is doubled, the magnitude of the electro-static force between them will be

  回答

  (C)

  a quarter of its former value
• 35

  Which of the following methods CANNOT be used to produce a steel magnet? The

  回答

  (D)

  heating of the specimen
• 36

  A cell gives a current of 0.15A through a resistance of 8\(\Omega\) and 0.3A. When the resistance is changed to 3\(\Omega\) the internal resistance of the cell is

  回答

  (D)

  2.00\(\Omega\)
• 37

  Which of the following will convert a milliammeter to a voltmeter?

  回答

  (C)

  high series resistance
• 38

  A wire P has half the diameter and half the length of a wire Q of similar material. The ratio of the resistance of P to that of Q is

  回答

  (C)

  2 : 1
• 39

  An electric kettle, connected to a 240V mains, produces 6.0 x 10⁵J of heat energy to boil a quantity of water in 5 minutes. Find the resistance of the kettle.

  回答

  (B)

  28.8\(\Omega\)
• 40

  On which of the following does the operation of a moving coil ammeter depend? i. Electromagnetic induction ii. Force on a carrying-current conductor iii. Magnetic effect of an electric current

  回答

  (B)

  ii only
• 41

  Which of the following statements is NOT correct?

  回答

  (A)

  A galvanometer can be converted to an ammeter with a different range by connecting a high resistance in series
• 42

  A transformer has a primary coil with 500 turns and a secondary coil with 2500 turns. When the voltage input to the primary coil is 120V, the output is

  回答

  (B)

  600V
• 43

  Which of the following statements about electrolysis is NOT correct?

  回答

  (E)

  The mass of gas set free or metal deposited is proportional to the square of the current
• 44

  Which of the following statements is NOT correct?

  回答

  (D)

  Longsighted people need diverging spectacle lenses
• 45

  Which of the following features is NOT a characteristic of natural radioactivity?

  回答

  (B)

  Radioactivity is exhibited only by elements of mass number greater than 206