JAMB - Physics (2018)

1
A man walks 1km due east and then 1 km due north His displacement?
答え
(A)
√2km N 45°E
2
The density of 400cm\(^3\) of palm oil was 0.9gcm-3 before frying. If the density of the oil was 0.6gcm-3 after frying, assuming no loss of oil due to spilling, its new volume was?
答え
(B)
600cm\(^3\)
3
Natural radioactivity consists of the emission of
答え
(C)
α- particles, β - rays and y-rays
4
Which of the following is true of an electrical charge?
答え
(D)
All of the above
5
Which of the following does NOT describe the Image formed by a plane minor?
答え
(D)
Magnified
6
What is the resultant resistance of the circuit in the image shown?

答え
(A)
8Ω
7
Which of the following best describes the energy changes which take place when a steam engine drives a generator which lights a lamp?
答え
(C)
heat ----> Kinetic ----> Electricity ----> Heat and Light
8
Cathode rays are
答え
(D)
streams of electrons
9
A narrow beam of white light can be split up into different Colours by a glass prism. The correct explanation is that
答え
(C)
different colours of white light travel with different speeds in glass
10
The diagram shown represents a block-and-tackle pulley system on which an effort of W Newtons supports a load of 120.0N. If the efficiency of the machine is 40, then the value of W is?
答え
(D)
50.0N
11
What type of reaction is represented by the following scheme?
\(_{1} ^{2} X\) + \(_{1} ^{2} Y\) -----> \(_{2} ^{3} Z\) + \(_{0} ^{1} n\) + energy
答え
(A)
fusion reaction
12
The amount of heat needed to raise the temperature of 10kg of Copper by 1K is its
答え
(C)
heat capacity
13
The electrochemical equivalent of silver is 0.0012g/C. If 36.0g of silver is to be deposited by electrolysis on a surface by passing a steady current for 5mins, the current must be?
答え
(B)
100A
14
Shadows and eclipses result from the
答え
(D)
rectilinear propagation of light
15
Which of the following obeys Ohm's law?
答え
(A)
all metals
16
Which of the following statements are TRUE of isotopes?
I. Isotopes of an element have the same chemical properties because they have the same number of electrons
II. Isotopes of elements are normally separated using physical properties
III. Isotopes of an element have the same number of protons in their nuclei
答え
(D)
I, II and III
17
In the diagram given the hanging mass m2 is adjusted until m1 is on the verge of sliding. The coefficient of static
答え
(C)
\(\frac{m_2}{m_1}\)
18
Which of the following may be used to explain a mirage?
I. Layers of air near the road surface have varying refractive indices in hot weather
II. Road surfaces sometimes becomes invisible in hot weather
III. Light from the sky can be refracted upwards after coming close to the road surface.
答え
(A)
I and III only
19
In the diagram given if the atmospheric pressure is 760mm, the pressure in the chamber G Is
答え
(B)
830mm
20
Which of the following has the lowest internal resistance when new?
答え
(D)
Accumulator
21
The pitch of an acoustic device can be increased by
答え
(C)
increasing the frequency
22
One of the features of the fission process is that
答え
(A)
it leads to chain reaction
23
The linear expansivity of brass is 2 x 10\(^{-5}\) C\(^{-1}\). If the volume of a piece of brass is 15.00cm at 0°C, what is the volume at 100°C
答え
(B)
15.09cm\(^3\)
24
A lead bullet of mass 0.05 kg is fired with a velocity of 200 m/s into a lead block of mass 0.95 kg. Given that the lead block can move freely, the final kinetic energy after impact is
答え
(C)
50J
25
In a series R-L-C circuit at resonance, the voltages across the resistor and the inductor are 30V and 40V respectively. What is the voltage across the capacitor?
答え
(D)
40V
26
If the fraction of the atoms of a radioactive material left after 120years is \(\frac{1}{64}\), what is the half-life of the material? \(\frac{1}{64}\)
答え
(A)
20 years
27
In the diagram shown, which of the simple pendulum will resonate with P when set into oscillation?
答え
(B)
T
28
The time rate of loss of heat by a body is proportional to the
答え
(C)
difference in temperature between the body and its surroundings
29
A positively charged rod X is brought near an uncharged metal sphere Y and is then touched by a finger with X still in place. When the finger is removed, the result is that Y has
答え
(D)
a negative charge and a negative potential
30
Electrical appliances in homes are normally earthed so that
答え
(A)
a person touching the appliances is safe from electric shock
31
The process whereby a liquid turns spontaneously into vapour is called
答え
(B)
evaporation
32
The differences observed in solids, liquids and gases may be accounted for by
答え
(C)
the spacing and forces acting between the molecules
33
Convex mirrors are used as driving mirrors because images formed are
答え
(A)
erect, Virtual and diminished
34
Musical instruments playing the same note can be distinguished from one another owing to the difference in their
答え
(A)
quality
35
In the diagram shown, If the south-poles of two magnets stroke a steel bar, the polarities at T and V will respectively be
答え
(C)
north and north
36
In homes, electrical appliances and lamps are connected in parallel because
答え
(D)
series connection uses high voltage
37
An object moves in a circular path of radius 0.5m with a speed of 1ms\(^{-1}\). What is its angular velocity?
答え
(D)
2rads\(^{-1}\)
38
What effort will a machine of efficiency 90% apply to a load of 180N if its efforts arm is twice as long as its load arm?
答え
(A)
100N
39
Calculate the effective capacitance of the circuit in the diagram given
答え
(D)
1μf
40
The inner diameter of a small test tube can be measured accurately using a
答え
(D)
Pair of vernier calliper
41
A pulley system has three pulleys in the fixed block and two in the movable block and if the pulley has an efficiency of 72%, the mechanical advantage of the system is?
答え
(D)
3.6
42
When an atom loses or gain a charge it becomes
答え
(B)
An ion
43
A ball of mass 800g moving horizontally with a speed of 5m/s hits a vertical wall and rebounds with the same speed. The impulse experienced by the ball is?
答え
(D)
8kgm/s
44
The force between the molecules of a liquid in contact with that of a solid is?
答え
(A)
Adhesive
45
A body of mass 100g moving with a velocity of 10ms-1 collides with a wall. If after collision it moves with a velocity of 2.0ms−1 in the opposite direction, calculate the change in momentum.
答え
(B)
1.2Ns
46
A 20kg mass is to be pulled up a slope inclined at 30° to the horizontal. If efficiency of the plane is 75%. The force required to pull the load up the plane is J [g=10ms\(^{− 2}\)]
答え
(C)
133.3N
47
The tendency of a body to remain at rest when a force is applied to it is called.
答え
(C)
Inertia
48
An object is placed 20cm from a concave mirror of focal length 10cm. The linear magnification of the image produced is?
答え
(C)
1
49
The energy needed to move a unit positive charge around a complete electric circuit is called the
答え
(B)
electric potential difference
50
A force of 5N acts at a point Y on a rod XYZ as shown in this diagram. If XYZ is 2m, what is the moment of the force about point X?
答え
(A)
0Nm
51
The resistance of a 40W car head lamp, drawing current from a 12V battery is ____.
答え
(C)
3.6Ω
52
A beam of light is incident from air to water at an angle of 30\(^o\). Find the angle of refraction if the refractive index of water is 4/3
答え
(C)
22\(^o\)
53
An electric heating coil rated at 1Kw is used to heat 2kg of water for 2 minutes. The initial water temperature is 30\(^o\)C. Taking the specific heat of the water as 4,000Jkg \(^{-1}\) and neglecting that of the container, the final water temperature is
答え
(B)
45.0\(^o\)C
54
What flows to the positively charged conductor by connecting it to the earth?
答え
(A)
Electrons
55
Temperature is the property of a body which is proportional to the ____.
答え
(B)
average kinetic energy of its molecules
56
The product of force and time is?
答え
(A)
Impulse
57
Which of the following concepts is not an evidence of the particles nature of matter?
答え
(D)
Esterification
58
A solid cube of side 50cm and mass 75kg floats in a liquid with \(\frac{1}{3}\) of its height above the liquid surface. The relative density of the liquid is?
答え
(D)
0.90
59
A man hears his echo from a nearby hill 2s after he shouted. If the frequency of his voice is 260Hz and the wavelength is 1.29m, how far away is the hill?
答え
(B)
335.4m
60
Which of the following is an essential physical property of the wires uses for making fuses ?
答え
(D)
Low melting point
61
A 40W instrument has a resistance 90 Ohms. On what voltage should it be operated normally
答え
(A)
60V
62
Mercury which is spilled onto a glass surface forms ball-like shapes because____.
答え
(B)
The cohesive force between its molecules is greater than the adhesive force between mercury and glass molecules
63
Water of mass 150g at 60\(^o\)c is added to 300g of water at 20\(^o\)c and the mixture is well stirred. Calculate the temperature of the mixture.(neglect heat losses to the surroundings)
答え
(A)
33\(^o\)c
64
Which of the following phenomena is the practical evidence for the existence of the continual motion of molecules.
答え
(C)
Brownian Motion
65
The process by which protons are converted into helium atoms with a tremendous release of energy is called?
答え
(C)
thermonuclear fusion
66
Which of the following is not a product of nuclear fusion?
答え
(A)
X – ray
67
A room is heated by means of a charcoal fire, an occupants of the room standing away from the fire is warmed mainly by
答え
(B)
Radiation
68
Which of the following phenomena cannot be explained by the molecular theory of matter?
答え
(D)
Radiation
69
The friction which exist between two layers of liquid in relative motion is called.
答え
(C)
Viscosity
70
A particle of mass M initially at rest splits into two. If one of the particles of mass M1 moves with velocity V1 , the second particle moves with velocity
答え
(B)
\(\frac{M1V1}{M1-M}\)
71
To keep a vehicle moving at a constant speed V requires power P from the engine. The force provided by the engine is
答え
(A)
\(\frac{P}{v}\)
72
Which of the following is the dimension of pressure
答え
(A)
ML\(^{−1}\)T\(^{−2}\)
73
Palm oil from a bottle flows out more easily after it has been heated because the
答え
(B)
Viscosity of oil is reduced
74
A ball of mass 5.0kg hits a smooth vertical wall normally with a speed of 2ms\(^{-1}\). Determine the magnitude of the resulting impulse
答え
(B)
10.0kgms\(^{-1}\)
75
The efficiency of energy conversion on the energy flow through a hydroelectric power is?
答え
(B)
\(\frac{E3}{E2}\)
76
An object weighs 30N in air and 21N in water. The weight of the object when completely immersed in a liquid of relative density 1.4 is
答え
(B)
17.4N
77
Which of the following instruments is most suitable for measuring the outside diameter of a narrow pipe in a few millimeters in diameter?
答え
(A)
Pair of calipers
78
Electrical power is transmitted at a high voltage rather than a low voltage because the amount of energy loss is due to
答え
(A)
Heat dissipation
79
If the focal length of a camera is 20cm, the distance from the film at which the lens must be set to produce a sharp image of 100cm away is
答え
(C)
25cm
80
The image of an object is located 6cm behind a convex mirror. If it's magnification is 0.6, calculate the focal length of the mirror
答え
(D)
-15.00cm
81
A lens of focal length 15cm forms an erect image which is three times the size of the object. The distance between the object and the image is ___.
答え
(D)
40cm
82
The photo cell works on the principle of the
答え
(B)
Emission of electron by incident radiation
83
When a known standard resistor of 2.0 is connected to the 0.0cm end of a metre bridge, the balance point is found to be at 55.0cm
答え
(B)
1.64Ω
84
A resistor connected to a 12V battery draws a current of 2A. The energy dispatched in the resistor in 5 minutes is ___.
答え
(C)
7,200J
85
A solid weighs 45N and 15N respectively in air and water. Determine the relative density of the solid
答え
(C)
1.50