A man standing on a lift that is descending does not feel any weight because
Trả lời
(C)
the lift's acceleration is same as acceleration due to gravity
2
Two balls X and Y weighing 5 g and 50 kg respectively were thrown up vertically at the same time with a velocity of 100 ms1 .How will their positions be one second later?
Trả lời
(D)
X and Y both be 500 m from the point of throw
3
If it takes an object 3s to fall freely to the ground from a certain height, what is the distance covered by the object?
Trả lời
(C)
45 m
4
An object of mass 2 kg moves with a velocity of 10 ms1 round at circle of radius 4 m. Calculate the centripetal force on the object
Trả lời
(C)
50 N
5
A carpenter on top of a roof of 20.0m high dropped a hammer of mass 1.5 kg and it fell directly to the ground. the kinetic energy of the hammer just before hitting the ground is?
[g = 10 ms-2]
Trả lời
(C)
300 J
6
If a tube of small radius opened at both ends is placed in a liquid, the liquid will
Trả lời
(C)
falls below the liquid level if the liquid does not wet the glass
7
An object weighs 22 kg in water and 30kg in air. what is the upthrust exerted by the liquid on the object.
[g = 10 ms2]
Trả lời
(D)
80 N
8
A metal of volume 40 cm3 is heated from 30 °c to 90 °c, the increase in volume is
Trả lời
(E)
no correct option
9
A copper wire was subjected to a tensile stress of 7.7 x 10\(^7\). Calculate the strain of the wire.
[Young modules = 1.1 x 10\(^11\) Nm\(^{-2}\)]
Trả lời
(C)
7.0 x 10-4
10
I. High thermal capacity.
II. High sensitivity.
III.Easy readability.
IV. Accuracy over a wide range of temperature
From the statement above, the qualities of a good thermometer are
Trả lời
(D)
II, III and IV
11
A machine is used to lift a load of 20 N through a height of 10 m. if the efficiency of the machine is 40%, how much work is done?
Trả lời
(B)
500 J
12
I. Density of the liquid.
II. Depth below the surface of the liquid.
III. Surface area of the liquid.
In which of the statement above will pressure be dependent?
Trả lời
(A)
I and II only.
13
Which of the following could be effectively used to reduce friction?
Trả lời
(B)
grease
14
Which of the following types of waves needs a medium for propagation?
Trả lời
(A)
sound waves
15
Which of the following electromagnetic waves has the highest frequency?
Trả lời
(C)
x - rays
16
A perfect emitter or absorber of radiant energy is a
Trả lời
(B)
black body
17
The ground is always cold at night because the
Trả lời
(B)
earth radiates heat to the atmosphere at night
18
A cannon is fired from town X,after how long is the sound heard at a town Y 4.95 km away?
[velocity of sound in the air = 330 ms-1]
Trả lời
(D)
15 s
19
The phenomenon that shows that increase in pressure lowers the melting point can be observed in
Trả lời
(D)
regelation
20
A block of aluminum is heated electrically by a 30 w heater if the temperature rises by 10°c in 5 minutes, the heat capacity of the aluminum is
Trả lời
(A)
900 JK-1
21
Steam burn is more severe than that of boiling water because
Trả lời
(B)
steam possesses greater heat energy per unit mass
22
I. change of state
II. Diffusion
III. Radiation
IV. Osmosis
which of the processes above can be explained using the kinetic theory?
Trả lời
(D)
I, II and IV
23
Three similar cells each of e.m.f 2 v and internal resistance 2Ω are connected in parallel, the total e.m.f and total internal resistance are respectively
Trả lời
(B)
2 v, 0.7Ω
24
When the human eye loses its power of accomodation, the defect is known as
Trả lời
(B)
presbyopia
25
When a red rose flower is observed in blue light, what colour does the observer see?
Trả lời
(E)
No correct option
26
The capacitance of a parallel plate capacitor is 20 μf in air and 60 μf in the presence of a dielectric. What is the dielectric constant?
Trả lời
(C)
3.0
27
A certain far - sighted person cannot see object that are closer to the eye than 50 cm clearly. Determine the power of the converging lens which will enable him to see at 25 cm
Trả lời
(B)
0.02 D
28
The eclipse of the sun occurs when the
Trả lời
(A)
moon is between the sun and the earth
29
Which of the following is a property of steel?
Trả lời
(C)
it can be used for making permanent magnets
30
In measuring high frequency a.c, the instrument used is the
Trả lời
(D)
hot wire ammeter
31
If the charge of electricity is K wh is N4, what is the cost of operating an electrical appliance rated 250 v,2 A for six hours?
Trả lời
(B)
N12
32
Under which of the following conditions do gases conduct electricity?
Trả lời
(B)
low pressure and high p.d
33
Two inductors of inductance 4 II and 8 II are arrange in series and a current of 10 A is passed through them. What is the energy stored in them?
Trả lời
(A)
600 J
34
Which of the following materials has an increase in resistance with temperature?
Trả lời
(B)
metals
35
The bond between silicon and germanium is
Trả lời
(A)
covalent
36
A radioactive isotope has a decay constant of 10-5s4. Calculate half life
Trả lời
(C)
6.93 x104s
37
The electrical properties of germanium can be altered drastically by the addition of impurity. This process is referred to as
Trả lời
(D)
dopping
38
If the threshold frequency for tungsten is 1.3 x 1015Hz, what is its work function?
[H = 6.6 x 10-34 Js]
Trả lời
(A)
8.58 x 10-19 J
39
Which of the following will be applied when a metal Y is used to electroplate another metal X in electrolysis?
Trả lời
(D)
Y is the anode and very high current is used
40
The diagram above shows two vectors at right angles to each other. The value of the resultant vector is
Trả lời
(B)
10.0 N
41
The diagram above show the positions of a cone. The position which can be described as neutral equilibrium is represented as
Trả lời
(A)
Z only
42
The correct expression for the potential at a point distance r from a charge q in an electric field is?
Trả lời
(D)
\(\frac{q}{4πε_or}\)
43
An image in a convex lens is upright and magnified 3 times. If the focal length of the lens is 15 cm, what is the object distance?
Trả lời
(A)
10 cm
44
A length of wire has a frequency of 225Hz when stretched by a force of 225N. If the force increased to 324N, what is the new frequency of vibration?
Trả lời
(A)
270 Hz
45
In the circuit above, three resistors, 2Ω, 4Ω and 12Ω are connected in parallel and a 12V battery is connected across the combination. The current flowing through the 12Ω resistors is
