Which of the following statements are true of the law of universal gravitation?
Răspuns
(C)
any two bodies attract each other with a force which is proportional to the product of their masses and inversely proportional to the square of the distance between them
2
Which of the following is true of an electrical charge?
Răspuns
(D)
all of the above
3
Which of the following statements are true in the structure of atoms?
Răspuns
(B)
the num,ber of protons equals the number of electrons
4
Which of the following are true of atom?
Răspuns
(D)
all of the above
5
A magnet is similar to a bipolar charged system in that
Răspuns
(E)
A and C only
6
In the study of physics, temperature and heat are often confused with each other. Which of the following statements correctly defines these two element?
Răspuns
(D)
all of the above
7
A given quantity of heat increases the temperature of 150grams of water from 9oC to 15oC and increases the temperature of oil of 100grams from 9oC to 25oC. The ratio of the specific heat of oil to that of water is
Răspuns
(C)
0.56
8
Which of the following physical quantities is NOT a vector?
Răspuns
(B)
work
9
The motion of the moving skin of a talking drum can rightly be described as
Răspuns
(D)
oscillatory
10
which of the following does NOT cause a reduction of the surface tension of water?
Răspuns
(E)
grease
11
The water at the bottom of a waterfall is slightly warmer than that at the top because part of the
Răspuns
(C)
kinetic energy is changed intyo internal energy
12
a pressure cooker saves both time and fuel in cooking because inside the cooker, the
Răspuns
(A)
boiling point of water is raised
13
Which of the following statements is NOT true of the image in a plane mirror? The image is
Răspuns
(D)
magnified
14
Any line or section through an advancing wave in which all the particles are in the same phase is called the
Răspuns
(E)
wave front
15
The name given to the characteristics behavior of substances which set their length perpendicular to a strong magnetic field instead of in line with it is
Răspuns
(C)
diamagnetism
16
Which of the following statements on the use of X-rays is incorrect? X-rays are used
Răspuns
(C)
in detecting fingerprints
17
What is the relative permitivity of a capacitor if its capacitance with a medium as dielectric is 16 farads and its capacitance with vacuum as dielectric is 2 farads?
Răspuns
(D)
8
18
If the magnification of a virtual image formed of an object 10cm from a convex lens is 3, then the focal length of the lens is
Răspuns
(B)
15cm
19
A quantity of sungas at -133 occupies 1/3m3 under pressure 1.4 x 105 Nm-2. if the gas occupies 31 m-2 at 37oC, its pressure will be
Răspuns
(B)
3.3 x104Nm-2
20
A stand-by generator is connected to fifteen 40 W lamps and musician's 600 W amplifying system. How much energy is used if the generator runs for 6 hours?
Răspuns
(B)
7.20k Wh
21
A tugboat is travelling from Asaba to Onitsha across the River Niger with a resultant velocity of 20 knots. If the river flows at 12 knots, the direction of motion of the boat relative to the direction of water flow is?
Răspuns
(B)
53.13o
22
A milliameter of resistance 5\(\Omega\) and full scale deflection of 50m A is to used to measure a potential difference of 50 V. The resistance of the multiplier should be
Răspuns
(D)
995\(\Omega\)
23
An object of mass m and volume v, is totally immersed in a liquid of density p. The tension of a string holding it is
Răspuns
(C)
(m - pv)g
24
The relative densities of zinc, brass, copper, gold and silver are respectively 7.1, 8.5, 8.9, 19.3, 10.5. A metal ornament which weighs 0.425kg and can displace 50 x 10-6m3m of water is made of
Răspuns
(B)
brass
25
Heat is supplied to a block of ice 0o until half of it has melted. Which of the following statements is true?
Răspuns
(B)
the temperature remains constant and the volume of ice decreases
26
If the volume of a fixed mass of a gas is kept constant, the pressure of the gas
Răspuns
(D)
is directly proportional to its absolute temperature
27
Which of the following statements about sound is NOT true?
Răspuns
(C)
sound travels through a vacuum
28
In a compound microscope
Răspuns
(B)
the objective lens have a shorter focal length than the eyepiece which is convex
29
In sunlight, a blue flower looks blue because we see the flower by the light it
Răspuns
(E)
reflects
30
High Tension(H.T.) transmission means
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(E)
trasmission of power at low current and high voltage
31
The best material for the core of the primary and secondary coils of an induction coil is
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(D)
soft iron, because it becomes magnetic but easily loses its magnetism
32
Which of the following radiations cannot be deflected by a magnetic field?
Răspuns
(C)
\(\gamma\)
33
Which of the following elements is the best absorber of X-rays?
Răspuns
(E)
lead
34
a calorimeter of thermal capacity 80j contains 20g of water at 25oC. Water at 100oC is added so that the final temperature of the set-ups is 50oC. The amount of water added is (Heat capacity of water = 4.18J/g/oC)
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(A)
20g
35
the ratio of the linear expansivity of copper to that of iron is approximately 1.5. A specimen of iron and a specimen of copper expands by the same amount per unit rise in temperature. The ratio of their length is
Răspuns
(E)
0.67
36
A man stands one-third of the way between two walls and claps his hands, He hears two distinct echoes 1s apart. If the speed of sound is 330ms-1 the distance between the wall is
Răspuns
(E)
495m
37
A cell has an open circuit voltage V1 and a closed circuit voltage V2 when a current is flowing through it. Therefore, the internal resistance of the cell is
Răspuns
(D)
\(\frac{(V_1 - V_2)}{I}\)
38
According to Ohm's law, the ratio V/I is constant for
Răspuns
(D)
silver
39
In the process of electrification by induction, the amount of induced charge in relation to the inducing charge is the
Răspuns
(E)
opposite in sign but equal
40
The activity of a radioactive substance depends on
