A copper cube weighs 0.25 N in air, 0.17N when completely immersed in paraffin oil and 0.15 N when completely immersed in water.The ratio of upthrust in oil to upthrust in water is
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(B)
4 : 5
2
A wheel and axle is used to raise a load of 500 N by the application of an effort of 250 N. If the radii of the wheel and the axle are 0.4 cm and 0.1 cm respectively, the efficiency of the machine is
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(C)
50 %
3
The hydrostatic blood pressure difference between the head and the feet of a boy standing straight is 1.65 x 104 Nm-2. Find the height of the boy.
[ Density of blood = 1.1 x 103 kgm-3, g = 10ms-2]
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(C)
1.5 m
4
A body weighing 80N stands in an elevator that is about to move. The force exerted by floor on the body as the elevator moves upward with an acceleration of 5 ms-2 is
[g = 10ms-2]
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(C)
120 N
5
If the distance between two suspended masses 10kg each is tripled, the gravitational force of attraction between them is reduced by
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(D)
one ninth
6
Two force each of 10N acts on a body, one towards the north and the other towards the east.
The magnitude and the direction of the resultant force are
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(D)
10√2N, 45°E
7
A particle in circular motion performs 30 oscillation in 6 seconds. Its angular velocity is
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(D)
10π rad s-1
8
The effect of a particle in a fluid attaining its terminal velocity is that the
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(B)
weight is equal to the retarding force
9
A coin place below a rectangular glass block of thickness 9cm and refractive index 1.5 is viewed vertically above the block. The apparent displacement of the coin is
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(A)
3 cm
10
The radiator of a motor car is cooled by
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(C)
convection
11
I. Temperature.
II. Density of air molecules
III. Pressure
IV. Pitch
Which of the above will affect the velocity of sound in the air
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(A)
I and II only
12
Which of the following is a characteristics of stationary waves?
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(A)
They are formed by two identical waves travelling in opposite directions
13
To produce an enlarged and erect image with a concave mirror,the object must be positioned
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(D)
between the principal focus and the pole
14
the property that is propagated in a traveling wave is
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(C)
energy
15
Which of the following eye defects can be corrected using a cylindrical lens.
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(B)
Astigmatism
16
The time rate of loss of heat by a body is proportional to the
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(A)
difference in temprature between the body and its surroundings
17
If tension is maintained on a stretched string of length 0.6m, such that its fundamental frequency of 220Hz is excited, determine the velocity of the transverse wave in the string.
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(B)
264 ms-1
18
A concave mirror of radius of curvature 40 cm forms a real image twice as large as the object.
the object distance is
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(B)
30 cm
19
water is a poor thermometric liquid because it
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(C)
wets glass
20
a ray of light which strikes a glass slab from air at normal incidence passes through the slab
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(A)
undeviated and undisplaced at a lower speed
21
blowing air over a liquid aids evaporation by
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(B)
decreasing its vapour pressure
22
The phenomenon that makes sound persist when its source has been removed is known as
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(D)
reverberation
23
the pressure of 3 moles of an ideal gas at a temperature of 27°C having a volume of 10-3m3 is
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(D)
7.47 x 106-2
24
Vibration in a stretched spring cannot be polarized because they are
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(C)
longitudinal waves
25
The diagram above show s the force-extension curve of a piece of wire. The energy stored when the wire is stretched from E to F is?
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(D)
7.5 x 10-1J
26
The diagram above shows the force (F) acting on an object through a distance (x). The work done on this object is expressed as
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(B)
Fx/2 J
27
Calculate the refractive index of the material for the glass prism in the diagram above
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(C)
√2
28
From the diagram above, determine the value of the resistance X
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(D)
15Ω
29
The energy stored in a capacitor of capacitance 10μF carrying a charge of 100μC
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(D)
5 x 10-4 J
30
When connected to a mains of 250V, the fuse rating in the plug of an electric device of 1 KW is
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(C)
4 A
31
The eye controls the amount of light reaching the retina by adjusting the
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(B)
iris
32
An electric iron is rated 1000W, 230V. What is the resistance of its elements?
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(B)
52.9Ω
33
The electric field between two - point charges is shown in the diagram above. What types of charges are at X and Y?
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(B)
Both X and Y are positive
34
The electromagnetic wave that can produce a heating effect on the environment is
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(C)
infrared rays
35
an electric cell with nominal voltage E has a resistance of 3Ω connected across it. If the voltage falls to 0.6E, the internal resistance of the cell is
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(B)
2Ω
36
\(^{23}_{11}\)Na + X → \(^{20}_9\)F + \(^4_2\)He
What particle is X in the reaction above?
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(C)
Neurons
37
Pure silicon can be converted to a p-type by adding a controlled amount of
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(A)
trivalent atoms
38
The energy associated with the photon of a radio transmission at 3 x 105 Hz is
[h = 6.63 x 10-34Js]
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(A)
2.00 x 10-28J
39
The percentage of the original nuclei of the sample of a radioactive substance left after 5 half - lives is
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(C)
3%
40
From the generating station to each substation power is transmitted at a very high voltage so as to reduce
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(D)
heating in the coils
41
The particle that is responsible for the nuclear fission in a nuclear reactor is
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(A)
neutron
42
A transistor is used in the amplification of signals because it
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(A)
controls the flow of current
43
The carbon-granules microphone works on the principle of change in
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(B)
resistance
44
At what frequency would a capacitor of 2.5μF used in the radio circuit have a reactance of 250Ω
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(B)
\(\frac{800}{\pi}\) Hz
45
A current of 0.5 A flowing 3h Deposits 2g of metal during electrolysis. The quantity of the same metal that would be deposited by the currents of 1.5A flowing in 1h is
