JAMB - Physics (1995)

1
Which of the following is the dimension of pressure?
Jawab
(A)
ML^-1T^-2
2
The length of a displaced pendulum ball which passes its lowest point twice every seconds is [g = 10ms-2]
Jawab
(A)
0.25 m
3
When a ball rolls on a smooth level ground, the motion of its center is
Jawab
(A)
translational
4
What is the acceleration due to gravity 'g' on the moon, if g is 10^-2 on the earth?
Jawab
(C)
1.6ms^-2
5
A body is projected from the earth's surface with the intention of letting it escape from the earth's gravitational field. What is the minimum escape velocity of the body? [Earth's radius = 6.4 x 10³km, g = 10ms^-2]
Jawab
(D)
11 kms^-1
6
A uniform rod PQ of length 1m and mass 2kg is pivoted at the end p. If load of 14N is placed at the center of the rod, find the force that should be applied vertically upwards at Q to maintain the rod at equilibrium horizontally [g = 10ms^-2]
Jawab
(C)
17N
7
A vehicle of mass m is driven by an engine of power P from rest. Find the minimum time it will take to acquire a speed
Jawab
(A)
\(\frac{mv^2}{2p}\)
8
Which of the following statements are TRUE about frictional force? i. it is always a disadvantage ii. it is sometimes a disadvantage iii. it always exist where there is a relative motion of two bodies that are in contact iv. it is sometimes very useful
Jawab
(D)
iii, iv only
9
The energy contained in a wire when it extended by 0.02m by a force 500 N is
Jawab
(A)
5J
10
A hydraulic press has a large circular piston of radius 0.8m and a circular plunger of radius 0.2m. A force of 500N is exerted by the plunger. Find the force exerted on the piston
Jawab
(A)
8000N
11
The volume of an air bubble increases from the bottom to the top of a lake at constant temperature because
Jawab
(B)
pressure increases with depth
12
Temperature is the measure of the
Jawab
(B)
mean kinetic energy of the molecules of the object
13
A rectangular metal block of volume 10\(^{-6}\)m\(^3\) at 273k is heated to 573k. If its coefficient of linear expansion is 1.2 x 10\(^{-5}\)k\(^{-1}\), the percentage change of it volume is
Jawab
(B)
1.1%
14
A piece of wood floats inside water at room temperature with a fraction of it above the liquid surface. As the temperature of the water is raised, the part of the wood above the liquid will
Jawab
(A)
decrease because the density of water decreases with temperature
15
The equation PxVyTz = constant in charles' law when
Jawab
(B)
x = 0, y = 1, z = -1
16
An electric kettle with negligible heat capacity is rated at 2000W. If 2.0kg of water is put in it, how long will it take the temperature of water to rise from 20^OC to 100^OC? [specific heat capacity of water = 4200Jkg^-1k^-1]
Jawab
(B)
336S
17
A temperature scale has a lower fixed point of 40mm and a upper fixed point of 200mm. What is the reading on this scale when a thermometer reads 60^oC?
Jawab
(D)
136.0mm
18
A quantity of ice at 10^oC is heated until the temperature of the heating vessel is 90^oC. Which of the following constants is NOT required to determine the quantity of heat supplied to the vessel?
Jawab
(D)
specific latent heat of vaporization
19
Which of the following statements give the TRUE difference between evaporation and boiling? i. Evaporation occurs at all temperatures while boiling occurs at a fixed temperature for a given pressure. ii. Evaporation is a surface phenomenon while boiling is an interior phenomenon. iii. Evaporation is affected by surface area while boiling is not.
Jawab
(D)
i, ii, iii.
20
A well-lagged bar of length 100cm has its ends maintained at 100^oC and 40^oC respectively. What is the temperature at a point 60cm from the hotter end?
Jawab
(D)
76^oC
21
Which of the following is the exclusive property of a transverse wave?
Jawab
(D)
polarization
22
The wavelength of signals from a radio transmitter is 1500mm and the frequency is 200kHz. What is the wavelength for a transmitter operating at 100kHz?
Jawab
(B)
300m
23
The difference between sound waves and light waves is that sound waves
Jawab
(B)
require a medium to travel while light waves does not
24
The pitch of an acoustic device can be increased by
Jawab
(A)
increasing the frequency
25
Total eclipse of the sun occurs when the
Jawab
(C)
moon is between the sun and the earth
26
What is the approximate critical angle for total internal reflection for diamond if the refractive index of diamond is 2.42?
Jawab
(D)
24^o
27
A real object is placed at a distance ucm in front of a curved mirror of focal length fcm. If the image is upright and magnified, then the mirror is
Jawab
(B)
concave and u = 2f
28
Which of the following pairs of colours gives the widest separation in the spectrum of white light?
Jawab
(A)
Red and Violet
29
Two parallel plates at a distance of 8.0 x 10^-3m apart are maintained at a p.d of 600 volts with the negative plate earthed. What is the electric field strength?
Jawab
(D)
75000.0Vm^-1
30
At different locations on the earth's surface, the earth's magnetic field is
Jawab
(C)
different in both magnitude and direction
31
If a resistance is halved in value and the potential difference across it is tripled, then the ratio of the new current to the old one is
Jawab
(D)
6 : 1
32
A 12V battery has an internal resistance of 0.5W.If a cable of 1.0W resistance is connected across the two terminals of the battery, the current drawn from the battery is
Jawab
(B)
8.0A
33
The purpose of a dielectric material in a parallel plate capacitor is to
Jawab
(C)
insulate the plate from each other
34
An electric current of 2 amperes flows in a heating coil of resistance 50 ohms for 3 minutes 20 seconds. Determine the heat produced
Jawab
(D)
40.0kJ
35
If the maximum voltage across a 100ohms resistor is 20V, then the maximum power it can dissipate is
Jawab
(B)
4.00W
36
Which of the following is required to convert a milliammeter to an ammeter?
Jawab
(C)
A low resistance in parallel
37
The primary winding of a transformer has 400 turns and its secondary has 100 turns. If a source of e.m.f. of 12V is applied to the primary, the secondary e.m.f. will be
Jawab
(A)
3V
38
A light of energy 5eV falls on a metal and the electrons with a maximum kinetic energy of 2eV are ejected. The work function of the metal is
Jawab
(C)
3.0eV
39
The half-life of a radio-active element is 9 days, what fraction of atoms has decayed in 36 days?
Jawab
(D)
\( \frac{15}{16} \)
40
An alternating source is connected in series to a capacitor of capacity reactance \( 10^3 \sqrt{3} \) and a resistor of resistance 10³ Ohms. The Impedance of the circuit is...
Jawab
(B)
2000 Ohms
41
In the above fig, PQ and R are vectors, which of the following options, gives a correct relationship between the vectors?
Jawab
(A)
P = Q + R
42
The value of T in the figure above is
Jawab
(D)
40.0N
43
The acceleration of the system show above is
Jawab
(B)
4ms^-2
44
A body of mass 40kg is being dragged along the floor by a rope inclined at 60 degrees to the horizontal. The frictional force between the box and the floor is 100N and the tension on the rope is 300N. How much work is done by dragging the box for a distance of 4m
Jawab
(C)
200J
45
The fig above shows two similar bulbs X and Y connected to suitable power supply with F as an appropriate fuse rating, if the filament of X breaks then the
Jawab
(B)
Brightness Of Y will remain constant