JAMB - Physics (1986)

1
Which of the following represents the correct precision if the length of a piece of wire is measured with a meter rule?
Answer
(A)
35mm
2
A heavy object is suspended from a string and lowered into water so that it is completely submerged. The object appears lighter because
Answer
(C)
it experiences an upthrust
3
Which of the following is a derived unit?
Answer
(D)
Newton
4
Two objects, one having three times the mass of the other, are dropped at the same time from a tall building. When they are above the ground, the two objects will have the same?
Answer
(D)
Acceleration
5
Which of the following is in a neutral equilibrium?
Answer
(B)
a cone resting on its slant edge
6
A ball is thrown vertically into the air with an initial velocity u. What is the greatest height reached?
Answer
(D)
\(\frac{u^2}{2g}\)
7
Which of the following assumptions is made in a simple pendulum experiment? the
Answer
(A)
suspending string is inextensible
8
A constant force of magnitude F acts on an object of mass 0.04kg initially at rest at a point O. if the speed of the object when it has moved 50m from O is 500ms-1, what is the value of F?
Answer
(B)
100.0N
9
A rectangular tank contains water to a depth of 2m, if the base is 4m x 3m, calculate the force on the base (Density of water = 103kgm-3, g = 10ms-2)
Answer
(B)
24 x 104N
10
A 1000kg elevator is descending vertically with an acceleration of 1.0ms-2, if the acceleration due to gravity is 10ms-2, the tension in the suspending cable is
Answer
(C)
9000.0N
11
The mode of heat transfer which does not require a material medium is
Answer
(B)
radiation
12
The expansion of solids can be considered a disadvantage in the?
Answer
(A)
balance wheel of a watch
13
The specific latent heat of fusion of lead is the amount of heat required to
Answer
(C)
change the state of a unit mass of lead at its melting point
14
Which of the following is common to evaporation and boiling? They
Answer
(C)
involve change of state
15
Mercury is suitable as a barometric fluid because it?
Answer
(C)
is several times denser than water
16
Which of the following properties makes metals ideal for cooking utensils?
Answer
(B)
good conduction of heat
17
A gas occupies a volume of 300cm3at a temperature of 27oC. What is its volume at 54oC, when the pressure is constant?
Answer
(C)
327cm3
18
When two objects P and Q are supplied with the same quantity of heat, the temperature change in P is observed to be twice that of Q. The ratio of the specific heat capacity of P to Q is
Answer
(C)
1 : 1
19
Which of the following is true of sounds?
Answer
(C)
the wavelength of a given sound wave in air decreases as the temperature increases
20
A lens of focal length 12.0cm forms an upright image three times the size of a real object. The distance between the object and the images is
Answer
(B)
16.0cm
21
In which of the following arrangements is the wavelength in an increasing order?
Answer
(B)
Gamma rays, x-rays, infra-red ray, radiowaves
22
If the refractive index of glass is 1.5, what is the critical angle at the air-glass interface?
Answer
(B)
sin-1\(\frac{2}{3}\)
23
A dentist obtains a linear magnification of 4 of a hole in a tooth by placing a concave mirror at a distance, of 2.0cm from the tooth. The radius of Curvature of the mirror is
Answer
(B)
3.2cm
24
What is the effect of the increase in the size of the hole of a pin-hole camera on the image? it
Answer
(A)
gives a blurred image
25
A pencil is placed vertically between a concave mirror and its focal point. The image of the pencil in the mirror will be
Answer
(D)
virtual, erect and enlarged
26
A wave of frequency 10Hz forms a stationary wave pattern in a medium where the velocity is 20cms-1. The distance between adjacent nodes is
Answer
(A)
1.0cm
27
Which of the following is true of the loudness of sound? It
Answer
(A)
depends on the square of the amplitude of the vibrating body
28
A man clapping his hands at regular intervals observes that the echo of a clap coincides with the next clap. If the reflecting cliff is 160m away and the speed of sound is 320ms-1, what is the frequency of the clapping?
Answer
(A)
1 Hz
29
The vibration of an air column produces the sound in the
Answer
(C)
flute
30
Which of the following is NOT a part of a d.c. electric motor?
Answer
(D)
Transformer
31
Which of the following is stored by a dry Leclanche cell?
Answer
(D)
Chemical energy
32
Which of the following is true of magnetism?
Answer
(B)
The freely suspended bar magnet comes to rest in the geographic north-south direction
33
The angle between the magnetic meridian and the geographic meridian at a locality on the earth is the
Answer
(D)
angle of declination of the locality
34
The sign of the change on a charged glass rod may be determined with
Answer
(A)
a charged electroscope
35
If the inclination at Ibadan is 7oS, this means that
Answer
(B)
the earth's magnetic intensity at Ibadan makes angle 7o with the horizontal direction
36
The wavelength of ultraviolet radiation is 400nm. If the speed of light in air is 3 x 108ms-1, then the frequency of the ultraviolet radiation is
Answer
(D)
7.5 x 1014Hz
37
Which of the following is most strongly deflected by magnetic field?
Answer
(C)
\(\beta\) - particles
38
When a box of mass 45kg, is given an initial speed of 5ms-1 it slides along a horizontal floor a distance of 3m before coming to a rest. what is the coefficient of kinetic friction between the box and the floor? (G = 10ms-2)
Answer
(B)
\( \frac{5}{12} \)
39

In fig 9 the value of R is

Answer
(D)
6Ω
40
if the fig above E is an accumulator with negligible internal resistance. and the EMF 9.0V, The the total current is
Answer
(C)
1.0A
41

In fig 6, a ray of light in air strikes a glass plate at an angle of incidence 60 degrees, the reflected ray is observed to be perpendicular to the refracted ray, what is the refractive index of the glass

Answer
(A)
1.73
42
In an experiment in which molten naphthalene is allowed to cool, the cooling curve in fig 5 was obtained, the temperature \( 80^{\circ}C \) is known as
Answer
(C)
melting point
43

fig 4 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 system is 40% then the value of W is

Answer
(C)
50.0N
44
In fig 3, three forces F1, F2, and F3 acting at O are in equilibrium. If the magnitude of F1 is 10N,and the magnitude of F2 is 5N, find the magnitude of F3
Answer
(C)
13.2N
45

A uniform meter rule QR is balanced on a knife edge which is 55cm from R, when a mass of 10g is hung at P as shown above, the mass of the meter rule is

Answer
(C)
70g