Marching soldiers crossing a suspension bridge are usually advised to break their steps to avoid damaging the bridge owing to
Одговорити
(B)
resonance
2
The sharpness of the boundary of the shadow of an object is determined by the
Одговорити
(A)
intensity of light striking the object
3
A thin converging lens has a power of 4.0 diopters determined its focal length.
Одговорити
(D)
0.25m
4
A real image three times the size of an object is formed 24cm from a converging mirror. what is the focal length of the mirror.
Одговорити
(B)
6cm
5
The pair of physical quantities consisting of vectors only are
Одговорити
(C)
displacement and torque
6
In an ideal wheel an axle system, R stand for the radius of the wheel and r is the radius of the axle. the mechanical advantage is
Одговорити
(D)
R/r
7
An object is projected from a height of 80 m above the ground with a velocity of 40ms-1 at an angle of 30° to the horizontal. The time of flight [ g ≈ 10m/s\(^2\)
Одговорити
(B)
4 s
8
In an a.c circuit that contains only a capacitor, the voltage lags behind the current by
Одговорити
(B)
90°
9
the time it will take a certain radioactive material with a half-life of 50 days to reduce to 1/32of its original number is
Одговорити
(A)
250days
10
A proton moving with a speed of 1.0 x 10\(^6\)ms\(^{-1}\) through a magnetic field of 1.0T experiences a magnetic force of magnitude 8.0 x 10\(^{-14}\) N. The angle between the proton's velocity and the field is
[1.6 x 10\(^{-19}\)C]
Одговорити
(C)
30°
11
When impurities are added to semi-conductors, the conductivity of the semi-conductor
Одговорити
(B)
increases
12
A silicon material is dopped with an element of a certain group and an n-type semi-conductor is formed. the most likely group of the element is
Одговорити
(A)
V
13
The charge carriers in gasses are
Одговорити
(B)
electrons and ions
14
The ray which causes gas molecules to glow is known as
Одговорити
(A)
cathode ray
15
A transformer is rated 240v. If the primary coil is 4000 turns and the secondary voltage 12v, determine the number of turns in the secondary coil.
Одговорити
(A)
200
16
The current in a reverse-biased junction is due to?
Одговорити
(A)
minority carriers
17
which of the following materials is a conductor?
Одговорити
(C)
Sodium
18
When the temperature difference between the wet and dry bulbs of a hygrometer is high, this indicates that
Одговорити
(D)
the relative humidity is low
19
A 3m3 volume of liquid W of density 200kgm3 is mixed with another liquid L of volume 7m3 and density 150kgm-3. the density of mixture is?
Одговорити
(A)
165kgm-3
20
A body of mass 36kg falls through a viscous liquid which offers a drag force of 260N on the body. The upthrust on the body at terminal velocity is?
[g = 10ms\(^2\)]
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(A)
100N
21
The process whereby the molecules of different substances move randomly is called?
Одговорити
(D)
diffusion
22
I. reproducibility
II. Sensibility
III. High thermal capacity
iv. High accuracy
The quantities of a good thermometer include?
Одговорити
(A)
I, II and IV only
23
The process whereby a liquid turns spontaneously into vapour is called?
Одговорити
(D)
evaporation
24
I. Melting
II. Boiling
III. Refraction
IV. Conduction
Which combination of the above is evident of the molecular nature of matter?
Одговорити
(B)
I ,II and IV only
25
When very hot water is poured into two identical thin and thick glass tumblers in equal volumes, the thick one cracks because?
Одговорити
(D)
of the uneven expansion of glass
26
Satellite communication network makes use of?
Одговорити
(C)
radio wave
27
An electric device is rated 2000 W, 250 v. The correct fuse rating of the device is?
Одговорити
(B)
8 A
28
The north pole of a magnet can never be separated from the south pole because of the property knowledge as?
Одговорити
(C)
magnetic dipole
29
A car battery rated 45 A H is charged with a charger whose rating is 2.5A.How long will it take to charge the battery full?
Одговорити
(B)
18 hrs
30
The electric field intensity in a place where a charge of 10-10c experiences a force of 0.4N is?
Одговорити
(D)
4.0 x 109 NC-1
31
Two charged particles are projected into a region where there is a magnetic field perpendicular to their velocities. if the charges are deflected in opposite directions, which of the following statements is true of the charge?
Одговорити
(A)
the charge must be of opposite sign
32
The resistance of a piece of wire of length 20m has crossed-sectional area 8 x 10\(^{-6}\)m\(^2\)is?
[Resistivity of the wire = 4 x 10\(^{-7}\) Ω m]
Одговорити
(D)
1.0 Ω
33
The figure above shows a plot of angles of deviation through a glass prism when light is incident at θ degrees on the prism. The incident angle that produces the minimum deviation is
Одговорити
(D)
25o
34
The value of F in the figure above when in equilibrium is
Одговорити
(C)
20N
35
In the figure above, the coefficient of static friction is 0.5. If the tension in the string is T, the acceleration of the system in motion is
Одговорити
(A)
5 ms-2
36
If the system above is in equilibrium, the tension in the string Q is
Одговорити
(B)
9N
37
In the figure above, the work done by the force of 100N inclined at an angle of 60o to the object dragged horizontally to a distance of 8m is
Одговорити
(D)
400J
38
In the circuit diagram of a transistor above, the terminal P, Q and R represent
Two liquids L1 and L2 are contained in a U - tube. The height and the density of L1 are 8 cm and 103 kgm-3 respectively. If the density of L2 is 800 kgm-3, its height measured from the same level is
Одговорити
(B)
10 cm
41
106J of heat is required to boil off completely 2kg of a certain liquid. Neglecting heat lost to the surroundings, the latent heat of vaporization of the liquid is
Одговорити
(D)
5.0 x 105J kg-1
42
The figure above shows three capacitors, 2μF, 3μF and 6μF connected in series. If the p.d across the system is 12V, the p.d, across the 6μF capacitor is
Одговорити
(C)
2V
43
If the distance between two point charges its increased by a factor of four, the magnitude of the electrostatic force between them will be
Одговорити
(B)
1/16 of its former value
44
The velocity of sound in air will be doubled if it's absolute temperature is
Одговорити
(A)
Quadrupled
45
A force of 200N acts between two objects at a certain distance apart. The value of the force when the distance is halved is
