JAMB - Physics (1998)

1
A bullet fired at a wooden block of thickness 0.15m manages to penetrate the block. If the mass of the bullet is 0.025kg and the average resisting force of the wood is 7.5 x 10³N, calculate the speed of the bullet just before it hits the wooden block.
Respondre
(C)
300ms^-1
2
The velocity of a sound wave at 27oC is 360ms-1. Its velocity at 127oC is
Respondre
(C)
240√3 ms^-1
3
The physical quantity that has the same dimensions as impulse is
Respondre
(B)
momentum
4
A ball is moving at 18ms\(^{-1}\) in a direction inclined at 60º to the horizontal. The horizontal component to its velocity is
Respondre
(D)
9ms^-1 ·
5
In free fall, a body of mass 1kg drops from a height of 125m from rest in 5s. How long will it take another body of mass 2kg to fall from rest from the same height? [g = 10ms^-1·]
Respondre
(A)
5s
6
A ball of mass 0.15kg is kicked against a rigid vertical wall with a horizontal velocity of 50ms-1. If it rebounced with a horizontal velocity of 30ms-1, Calculate the impulse of the ball on the ball · ·
Respondre
(D)
12.0Ns
7
The force of attraction between two point masses is 10^-4N when the distance between them is 0.18m. If the distance is reduced to 0.06m, calculate the force.
Respondre
(D)
9.0 x 10^-4N
8
A uniform meter rule weighing 0.5N is to be pivoted on a knife-edge at the 30cm-mark. where will a force of 2N be placed from the pivot to balance the meter rule?
Respondre
(D)
5cm
9
A man whose mass is 80kg climbs a staircase in 20s and expends power of 120W. Find the height of the staircase.[g = 10ms^-2]
Respondre
(D)
3.0m
10
A parachute attains a terminal velocity when
Respondre
(B)
the viscous force of the air and the upthrust completely counteract its weight
11
In a wheel and axle mechanism the diameters of the wheel and axle are 40cm and 8cm respectively. Given that the machine is 80% efficient, what effort is required to lift a load of 100N?
Respondre
(B)
25N
12
The tendon in a man's leg is 0.01m long. If a force of 5N stretches the tendon by 2.0 x 10^-5m, calculate the strain on the muscle.
Respondre
(C)
2 x 10^-3
13
Which of these statements are correct for the pressures in liquids? i. pressure in a liquid at a point acts equally in all directions. ii. pressure increases with depth. iii. pressure at a depth depends on the shape of the container. iv. pressure at the same depth in different liquids are proportional to the density at different liquids.
Respondre
(B)
i, ii, iv only
14
The atmospheric pressure due to water is 1.3 x 10⁶Nm^-2. What is the total pressure at the bottom of an ocean 10m deep? [Density of water = 1000kgm^-3, g = 10ms^-2]
Respondre
(B)
1.4 x 10⁶Nm^-2
15
A solid of weight 0.600N is totally immersed in oil and water respectively. If the upthrust of oil is 0.210N and the relative density of oil is 0.875. Find the upthrust in water.
Respondre
(C)
0.240N
16
A platinum resistance thermometer records 3.0\(\Omega\) at 0^oC and 8.0\(\Omega\) at 100^oC. If it records 6.0\(\Omega\) in a certain environment, The temperature of the medium is
Respondre
(B)
60^oC
17
The linear expansivity of brass is 2 x 10^-5C^-1. If the volume of a piece of brass is 15.00cm³ at 0⁰C, What is the volume at 100^oC?
Respondre
(C)
15.09cm³
18
A gas has a volume of 100cm³ at 27^oC. If it is heated to temperature T until a final volume of 120cm³ is attained, calculate T
Respondre
(C)
87^oC
19
A 500W heater is used to heat 0.6kg of water from 25ºC to 100ºC in t\(_1\) seconds. If another 1000W heater is used to heat 0.2kg of water from 10ºC to 100ºC in t\(_2\), seconds, find \(\frac{t_1}{t_2}\)
Respondre
(B)
5
20
How many grams of water at 17^oC must be added to 42g of ice at 0^oC to melt the ice completely? [specific latent heat of fusion of ice = 3.4 x 10⁵Jkg^-1, specific heat capacity of water = 4200Jkg^-1k^-1]
Respondre
(A)
200g
21
A vapour is said to be saturated when
Respondre
(B)
a dynamic equilibrium exists between the molecules of the liquid and the vapour molecules at a given temperature
22
One valid assumption of the kinetic theory of gasses is the
Respondre
(D)
the molecules of gas are all identical and are very small in size
23
The physical properties of sound waves can best be described by
Respondre
(A)
reflection and diffraction
24
In a closed organ pipe producing a musical note, an antinode will always be produced at
Respondre
(B)
the open end
25
A steel wire of length 0.50m is stretched between two fixed points and its fundamental frequency is 200Hz. The speed of the wave in the wire is
Respondre
(C)
200ms^-1
26
In a resonance tube experiment, if the fundamental frequency of the vibrating air column is 280Hz, the frequency of the third overtone is
Respondre
(D)
1960Hz
27
An object 0 lies at a distance m in front of concave mirror of focal length f. If m < f, then the final image obtained will be
Respondre
(B)
magnified and erect
28
An object is placed in front of two plane mirrors inclined at an angle of 0^o. If the total number of images formed is 7, Find the value of \(\theta\)
Respondre
(B)
45^o
29
The most suitable type of mirror used for the construction of the search light is the?
Respondre
(D)
parabolic mirror
30
The displacement d produced in a glass block of thickness t and refractive index n when an object is viewed through it is
Respondre
(C)
t (1-1/n)
31
A man wears convex lens glasses of focal length 30cm in order to correct his eye defect. instead of the optimum 25cm, his least distance of distinct vision is
Respondre
(D)
150cm
32
Which of the following are true about the infra-red radiation? i. it is invisible ii. it is called heat ray iii. its frequency is higher than that of blue light iv. it travels as a transverse wave
Respondre
(B)
i, ii, iv only
33
The force of repulsion between two point positive charges 5\(\mu\)C and 8\(\mu\)C separated at a distance of 0.02m apart is. [\(\frac{1}{4{\pi}{\varepsilon}_o}\) = 9 x 10\(^9\)Nm\(^2\)C\(^{-2}\)]
Respondre
(C)
9.0 x 10²N
34
An ebonite rod rubbed with fur attracts a glass rod rubbed with silk because
Respondre
(A)
ebonite has a negative charge while glass has a positive charge
35
Which of the following can be used to reduce local action in a Laclanche cell?
Respondre
(C)
Potassium permanganate solution in contact with the positive pole
36
Find the work done in moving a 2 C charge between two points X and Y in an electric field if the potential difference is 100 volts
Respondre
(C)
200J
37
A parallel plate capacitor has a common plate area of 5 x 10\(^{-8}\)m2 and plate separation of 2 x 10\(^{-3}\)m, Assuming free space,

What is the capacitance? [\(\varepsilon\)o = 9.0 X 10-\(^{-12}\)C2N-1m-2]
Respondre
(C)
2.25 x 10^-16F
38
The iron core of an induction coil is made from bundles of wire so as to
Respondre
(A)
minimize eddy-currents
39
Electricity is supplied to a school along a cable of total resistance 0.5\(\Omega\) with the maximum current drawn from the mains as 100A. The maximum energy dissipated as heat for 1 hr is
Respondre
(D)
1.8 x 10⁷J
40
A transformer which can produce 8V from a 240v a.c. supply, has an efficiency of 80%. If the current in the secondary coil is 15A, calculate the current in the primary coil.
Respondre
(A)
0.625A
41
The electrochemical equivalent of a metal is 1.3 x 10^-7kgC^-1. The mass of the metal which 2.0 x 10⁴C of electricity will deposit from a suitable electrolyte is
Respondre
(D)
2.6 x 10^-3kg
42
In a nuclear fusion experiment, the loss of mass amounts to 1.0 x 10^-6kg. The amount of energy obtained from the fusion is
Respondre
(D)
9.0 x 10¹⁰J
43
In photoelectric effect, electrons will leave the metal surface when illuminated by light of appropriate frequency if the photon energy is
Respondre
(A)
greater than the work function
44
A body on the ground is acted on by a force of 10N at a point P as shown in the fig above. What force is needed to stop the body from moving eastwards?
Respondre
(B)
5N in the diretion of west
45
The total resistance measured at PQ in the diagram above is
Respondre
(C)
4.0Ω