JAMB - Physics (2019)

1
The limiting frictional force between two surface depends on

I. the gaseous reaction between the surfaces

II. the nature of the surfaces in contact

III. the relative velocity between the surfaces

Trả lời
(C)
II only
2
If a body moves with a constant speed and at the same time undergoes an acceleration, its motion is said to be
Trả lời
(B)
circular
3
When blue and green colours of light are mixed, the resultant colour is
Trả lời
(A)
cyan
4
A metal rod has a length of 100cm at 200\(^oC\). At what temperature will its length be 99.4cm. If the linear expansivity of the material of the rod is 2 x 10\(^{-5}C^{-1}\)
Trả lời
(D)
-100\(^o\)C
5
According to kinetic molecular model, in gases
Trả lời
(A)
The molecule are very fast apart & occupy all the space made available
6

The value of T in the figure above is
Trả lời
(D)
40N
7
A train has an initial velocity of 44m/s and an acceleration of -4m/s\(^2\). Calculate its velocity after 10 seconds
Trả lời
(D)
4m/s
8
Lamps in domestic lightings are usually in
Trả lời
(D)
parallel
9
During the transformation of matter from the solid to the liquid state, the heat supplied does not produce temperature increase because
Trả lời
(A)
all the heat is used to break the bonds holding the molecules of the solid together
10
In a slide wire bridge, the balance is obtained at a point 25cm from one end of wire 1m long. The resistance to be tested is connected to that end and a standard resistance of 3.6\(\Omega\) is connected to the other end of the wire. Determine the value of the unknown resistance
Trả lời
(D)
1.2\(\Omega\)
11
Electrons were discovered by
Trả lời
(C)
J.J. Thompson
12
Which of the following is/are the limitations to the Rutherford's atomic models?

I. It is applicable when energy is radiated as electrons are revolving

II. It is applicable when energy is radiated in a continuous mode

III. It is applicable to an atom with only one electron in the other shell
Trả lời
(C)
I & II only
13
Which of the following equations is the correct definition of the reactance of an indicator L?
Trả lời
(A)
Reactance = (Amplitude of voltage) \(\div\) (Amplitude of current)
14
Ripple in a power supply unit is caused by
Trả lời
(A)
using an alternating current source
15
When the temperature of a liquid is increased, its surface tension?
Trả lời
(B)
decreases
16
The distance between an object and its real image in a convex lens is 40cm. If the magnification of the image is 3, calculate the focal length of the lens
Trả lời
(B)
7.5 cm
17
A ray of light passes through the centre of curvature of a concave mirror and strikes the mirror. At what angle is the ray reflected?
Trả lời
(C)
0\(^o\)
18
The pin-hole camera produces a less sharply defined image when the
Trả lời
(A)
pin-hole is larger
19
A straight wire 15cm long, carrying a current of 6.0A is in a uniform field of 0.40T. What is the force on the wire when it is at right angle to the field
Trả lời
(C)
0.36N
20
The pitch of a screw jack is 0.45cm and the arm is 60cm long. If the efficiency of the Jack is 75/π %, calculate the mechanical advantage.
Trả lời
(C)
200
21
When the downward current flows in a straight vertical conductor, the direction of its magnetic field at a point due north of the wire is?
Trả lời
(D)
West
22
Aluminium is sometimes used as the leaf of an electroscope because it
Trả lời
(D)
can be converted into thin sheets
23

The diagram above represents the stress-strain graph of a loaded wire. Which of these statements is correct?
Trả lời
(B)
J is the yield point
24
A supply of 400V is connected across capacitors of 3μf and 6μf in series. Calculate the charge
Trả lời
(A)
8 x 10\(^{-4}\)C
25
A vibrator causes water ripples to travel across the surface of a tank. The wave travels 50cm in 2s and the distance between successive crests is 5cm. Calculate the frequency of the vibrator
Trả lời
(A)
5Hz
26
A thermocouple thermometer is connected to a millivoltmeter which can read up to 10mV. When one junction is in ice at 0°C and the other is steam at 100°C, the millivoltmeter reads 4mV. What is the maximum temperature which this arrangement can measure
Trả lời
(C)
250\(^o\)C
27
An alternating current can induce voltage because it has
Trả lời
(B)
varying magnetic field
28
The limiting frictional force between two surfaces depends on
I. the cohesive force of the material
II. the nature of the surfaces in contact
III. the relative velocity between the surfaces
Trả lời
(B)
II only
29
During the transformation of matter from the solid to the liquid state, the heat supplied does not produce a temperature increase because
Trả lời
(D)
all the heat is used to break the bonds holding the molecules of the solid together
30
The statement 'Heat lost by the hot body equals that gained by the cold one' is assumed when determining specific that heat capacity by the method of mixtures. Which of the following validates the assumption?
I. Lagging the Calorimeter
II. Ensuring that only S.I units are used
III. Weighing the calorimeter, the lid and the stirrer.
Trả lời
(C)
I & III only
31
In the molecular explanation of conduction, heat is transferred by the
Trả lời
(A)
Free electrons
32
The conductivity of gases at low pressure can be termed as
I. hot cathode emission
II. thermo ionic emission
III. cold cathode emission
IV. Field emission
Trả lời
(C)
III & IV
33
Which of the following media allow the transmission of sound waves through them?
I. air
II. liquid
III. solids

Trả lời
(D)
I, II & III
34
The earth's gravitational field intensity at its surface is about
(G = 6.7 × 10\(^{-11}\)Nm\(^2\)/kg\(^2\), mass of the earth is 6 × 10\(^{24}\)kg, radius of the earth is 6.4 × 10\(^6\)m, g on the earth = 9.8m/s\(^2\))
Trả lời
(D)
9.8N/kg
35
The following are parts of the eye
I. Retina
II. Pupil
III. Iris
The correct equivalent in the camera in the same order are
Trả lời
(D)
Film, Aperture, Diaphragm
36
According to kinetic molecular model, in gases
Trả lời
(C)
The molecule are very fast apart & occupy all the space made available
37
A force of 6N acts horizontally on a stationary mass of 2kg for 4s. The kinetic energy gained by the mass is _________
Trả lời
(C)
144j
38
The momentum of a car moving at a constant speed in a circular track
Trả lời
(C)
can be zero depending on its inertia in the track
39
A metal rod has a length of 100cm at 200°C. At what temperature will its length be 99.4cm. If the linear expansivity of the material of the rod is 2 × 10\(^{-5}\)C\(^{-1}\)
Trả lời
(D)
\(-100^0C\)
40
The lead-acid accumulator consists of
Trả lời
(D)
tetraoxosulphate (vi) acid as the electrolyte
41
When water is boiling, it
Trả lời
(D)
changes to steam
42
A mixture of blue and red pigment when illuminated by white light will appear
Trả lời
(D)
magenta
43
A siren having a ring of 200 hole makes 132 rev/min. A jet of air is directed on the set of holes. Calculate the frequency and wavelength in air of the note produced (take v = 350m/s)
Trả lời
(A)
0.795m
44
A man on a bench will exert the greatest pressure on the bench when he
Trả lời
(D)
stands on the toes of one foot
45
Gases conduct electricity under
Trả lời
(D)
low pressure & high voltage
46
Neutrons were discovered by
Trả lời
(C)
James Chadwick
47
The mass of a nucleus is the
Trả lời
(A)
total number of its proton & neutrons
48
Three resistors with resistance 200Ω, 500Ω and 1kΩ are connected in series. A 6v battery is connected to either end of the combination. Calculate the potential difference between the ends of 200Ω resistance.
Trả lời
(A)
0.71V
49
An a.c of 1A at a frequency of 800 cycles per second flows through a coil, the inductance of which is 2.5mH and the resistance of which is 5Ω. What is the power absorbed in the Coil?
Trả lời
(A)
5W
50
In semi-conductor, the carriers of current at room temperature are
Trả lời
(B)
electrons and holes
51
Water and Kerosine are drawn respectively into the two limbs of a Hare's apparatus. The destiny of water is 1.0gcm\(^{-3}\) and the density of kerosine is 0.80gcm\(^{-3}\). If the height of the water column is 20.0cm, calculate the height of the kerosine column.
Trả lời
(D)
25.0cm
52
When a girl moves towards a plane mirror at a speed of 4.0m/s, the distance between the girl & her image reduces at a speed of
Trả lời
(C)
8 m/s
53
One newton × One meter equals?
Trả lời
(B)
One Joule
54
A microscope is focused on a mark on a table, when the mark is covered by a plate of glass 2m thick, the microscope has to be raised 0.67cm for the mark to be once more in focus. Calculate the refractive index.
Trả lời
(A)
1.50
55
Radio waves belongs to the class of waves whose velocity is about
Trả lời
(C)
3 × 10\(^{8}\) m/s
56
A single force which produces the same effect as a set of forces acting together at a point is known as the
Trả lời
(C)
resultant
57
Which of the following statement about the electromagnet shown above is correct?
Trả lời
(B)
when the current flows from A to B, the end A will be south pole
58
Calculate the velocity ratio of a screw jack of pitch 0.2cm if the length of the tommy bar is 23cm
Trả lời
(A)
230\(\pi\)
59
The Earth's magnetic equator passes through Jos in Nigeria. At Jos, the
Trả lời
(C)
angle of dip is zero
60
A car moving at 20m/s with its horn blowing (f = 1200Hz) is chasing another car going at 15m/s. What is the apparent frequency of the horn as heard by the driver being chased?
Trả lời
(A)
1.22KHz
61
Any line or section taken through an advancing wave in which all the particles are in the same phase is called the
Trả lời
(D)
wave front
62

In which of the points labelled A, B, C, D and E on the conductor shown would electric charge tend to concentrate most
Trả lời
(D)
E
63
The point at which the molecules of a loaded wire begin to slide across each other resulting in a rapid increase in extension is
Trả lời
(A)
yield point
64
The resultant capacitance in the figure above is
Trả lời
(B)
0.8μf
65
The lower fixed part of a faulty thermometer reads 2°C while the upper fixed point is 100°C.
What is the true temperature when the thermometer reads 51°C?
Trả lời
(B)
50°C
66
If a body moves with a constant speed and at the same time undergoes an acceleration, its motion is said to be
Trả lời
(A)
circular
67
A coil X is moved quickly away from the end Y of a stationary metal bar and a current then flows in X as shown above.
Then

Trả lời
(B)
Y is a north pole
68
A boy pushes a 500kg box along a floor with a force of 2000N. If the velocity of the box is uniform, the co-efficient of friction between the box and the floor is
Trả lời
(D)
0.4
69
The following are some units
I. Ns
II. Non
III. Nm\(^{-2}\)
IV. J°K\(^{-1}\)
V. JKg\(^{-1}\)
What are the units of latent heat?
Trả lời
(D)
V
70
When two objects A and B are supplied with the same quantity of heat, the temperature change in A is obtained to be twice that of B. The mass of A is half that of B. The ratio of the specific heat capacity of A to B is
Trả lời
(C)
1 : 1
71
The volume of 0.354g of helium at 273°C and 114cmhg of mercury pressure is 2667cm\(^3\). Calculate the volume
Trả lời
(A)
2000.25 cm\(^3\)
72
Which of these is observed when air is pumped out of a discharge tube without lowering its pressure
Trả lời
(C)
conduction does not occur
73
Which of the following characteristics of a wave is used in the measurement of the depth of the Sea?
Trả lời
(D)
reflection
74
If the attraction of the sun is suddenly ceased, the earth would continue to move in a straight line making a tangent with the original orbit. This statement is derived from Newton's
Trả lời
(A)
First law of motion
75
Heat may be transferred by conduction, convection and radiation. By which of these methods does heat travel through vacuum?
Trả lời
(C)
Radiation only
76
The part of the human eye that does similar work as the diaphragm of a camera lens is the
Trả lời
(C)
Iris
77
A projectile of mass 4kg is fired vertically and reaches a maximum height of 40m. Calculate the potential energy at the highest point
(g = 10ms\(^{-2}\)
Trả lời
(B)
1600J
78
The length of the seconds hand of laboratory clock is 0.1m. Calculate the speed at the top of the seconds hand
Trả lời
(A)
1.05 × 10\(^{-2}\)ms\(^{-1}\)
79
Workdone on an object to bring it to a certain point in space is called
Trả lời
(A)
Gravitational potential energy
80
A copper rod, 5m long, when heated through 10ºC, expands by 1mm. If a second copper rod, 2.5m long, is heated through 5ºC, by how much will it expand?
Trả lời
(B)
0.25mm
81
A safety precaution designed to prolong the life of a lead acid accumulator is
Trả lời
(C)
Keeping the specific gravity of the electrolyte within specified range
82
The mass of water vapour in a given volume of air is 0.05g at 20°C, while the mass of water vapour required to saturate it at the same temperature is 0.15g. Calculate the relative humidity of the air.
Trả lời
(C)
33.33%
83
The angular dispersion of a prism depends on
Trả lời
(A)
The index of refraction only
84
Which of the following statements are correct of the production and propagation of waves?
I. vibration produces waves
II. waves transmit energy along the medium
III. the medium through which the wave travels does not travel with the wave
IV. waves do not require any medium for transmission
Trả lời
(D)
I, II and III only
85
A rectangular solid block has length 10cm, breadth 5cm and height 2cm. If it lies on a horizontal surface, and has density 100kg/m\(^3\), calculate the pressure it exerts on the surface.
Trả lời
(A)
20 N/m\(^2\)
86
The diagram shows four positions of the bob of a simple pendulum. At which of these positions does the bob have maximum kinetic energy and minimum potential energy
Trả lời
(C)
None Of The Above
87
An object is acted upon by a system of parallel forces causing the object to be in state equilibrium. Which of the following statement is not correct
Trả lời
(C)
all the parallel forces must not be equal in magnitude and direction
88
Which of the following statements is/are correct for a freely falling body?
I. the total is entirely kinetic
II. the ratio of potential energy to kinetic energy is constant
III. the sum of potential and kinetic energy is constant
Trả lời
(C)
III only
89
Efficiency of conduction in liquids and gases compared to solids is
Trả lời
(A)
less efficient than solid
90
A well 1km deep is filled with a liquid of density 950kg/m\(^3\) and g = 10m/s\(^2\), the pressure at the bottom of the well is
Trả lời
(A)
9.6 × 10\(^6\)N/m\(^2\)
91
"Sum of all forces acting on a body is zero." This condition represents equilibrium'
Trả lời
(A)
First condition
92
Which of the following bodies, each with centre of gravity G, lying on a horizontal table, is/are in unstable equilibrium?
Trả lời
(B)
III only
93
The volume of a stone having an irregular shape can be determined using?
Trả lời
(B)
measuring cylinder
94
In Sunlight, a blue flower looks blue because we see the flower by the light it
Trả lời
(D)
reflect
95
A body moves in SHM between two point 20m on the straight line Joining the points. If the angular speed of the body is 5 rad/s. Calculate its speed when it is 6m from the center of the motion.
Trả lời
(C)
40 m/s
96
The diagram shows a uniform meter rule AB which balances horizontally at the 90cm mark when a mass of 0.2kg is suspended from B. Calculate the mass of the meter rule.
Trả lời
(A)
0.05kg
97
The equilibrium position of objects in any field corresponds to situation of
Trả lời
(C)
minimum potential energy
98
The height at which the atmosphere ceases to exist is about 80km. If the atmospheric pressure on the ground level is 760mmHg, the pressure at a height of 20km above the ground level is
(ρm = 13.6g/cm\(^3\) ρ = 0.00013g/cm\(^3\) )
Trả lời
(B)
570mmHg
99
A cone is in unstable equilibrium, has its potential energy
Trả lời
(B)
increased
100
A mass of 0.5kg is whirled in a vertical circle of radius 2m at a steady rate of 2 rev/s. Calculate the centripetal force
Trả lời
(C)
158N