Which of the following phenomena causes capillary of liquids in tubes of narrow bore?
Trả lời
(B)
surface tension
2
Which of the following physical quantities are derived? i. Area ii. Thrust iii. Pressure iv. Mass
Trả lời
(B)
i, ii and iii only
3
A block of volume 3 x 105m3 and density 2.5 x 103 kg m-3 is suspended from a spring balance with \(\frac{2}{3}\) of its volume immersed in a liquid of density 900 kg m-3. Determine the reading of the spring balance [g = 10ms-2]
Trả lời
(B)
0.57N
4
A solid body will float in a liquid if its
Trả lời
(A)
density is less than that of a liquid
5
An object is said to undergo oscillatory motion when it moves
Trả lời
(B)
to and fro about a fixed point
6
A body is rotating in a horizontal circle of radius 2.5m with an angular speed of 5 rad s-1. Calculate the magnitude of the radial acceleration of the body
Trả lời
(C)
12.50ms-2
7
A moving car of mass 800 kg experiences a frictional force of 200N. If it accelerates 2 ms-2, calculate the magnitude of the force applied to the car
Trả lời
(D)
1800N
8
Uniform speed occurs when there is equal change of
Trả lời
(A)
distance in equal times
9
A car accelerates uniformly from rest at 5 ms-2. Determine its speed after 10s
Trả lời
(A)
50.0ms-1
10
Which of the following quantities is a vector?
Trả lời
(D)
momentum
11
which of the following statements about simple harmonic motion is correct? The
Trả lời
(A)
total mechanical energy is always conserved
12
A force acting on a body causes a change in the momentum of a body from 12 kg ms-1 to 16kg ms-1 in 0.25. Calculate the magnitude of the impulse
Trả lời
(C)
4.0Ns
13
Which of the following source of energy is renewable?
Trả lời
(C)
hydro
14
A stone of mass 2.0kg is thrown vertically upward with a velocity of 20.0 ms-1, calculate the initial kinetic energy of the stone
Trả lời
(B)
400J
15
Which of the following statements about the mouth piece of a telephone is correct? It converts sound energy into
Trả lời
(C)
electrical energy
16
The potential energy in an elastic string of force constant K which has been extended by X metres is expresses as
Trả lời
(A)
\(\frac{1}{2}k \Box ^2\)
17
The engine of a train produces a force of 3000N when moving at 30.ms-1. calculate the power of the engine
Trả lời
(C)
9.00 x 104W
18
The velocity ratio of an inclined plane, inclines at an angle \(\theta\) to the horizontal can be expressed as
Trả lời
(A)
(sin \(\theta)^{-1}\)
19
A block and tackle system has six pulleys. a force of 50N applied to it lifts a load of weight W. If the efficiency of the system is 40%, calculate W
Trả lời
(D)
120N
20
The sagging of overhead electrical cables is the consequence of
Trả lời
(A)
linear expansivity
21
The silvered surface in a vacuum flask reduces heat loos due to
Trả lời
(C)
radiation
22
How long will it take to heat 3kg of water from 28oC to 88oC in an electric kettle taking 6a from a 220V supply? [specific heat capacity of water = 4180 J kg-1K-1]
Trả lời
(B)
570s
23
The amount of energy required to change a kilogram of ice in water without a change in temperature is
Trả lời
(D)
specific latent heat of fusion of ice
24
A quantity of steam at 100oC condenses to water at the same temperature by releasing 6.9 x 104J of energy. Calculate the mass of the condensed steam. [specific latent heat of vaporization of eater = 2.3 x 106 J kg-1]
Trả lời
(B)
3.0 x 10-2 kg
25
The temperature of a liquid falls after some of it has evaporated because
Trả lời
(B)
the more energetic molecules have escaped into the atmosphere
26
The S.I units of frequency, period and amplitude of a wave are respectively
Trả lời
(D)
hertz, second and metre
27
a note of frequency 2000Hz has a velocity of 400 ms-1. calculate the wavelength of the note
Trả lời
(D)
0.2m
28
The eclipse of the moon occurs when the
Trả lời
(B)
earth comes exactly between the moon and the sun
29
Which of the following observations cannot be explained using the rectilinear propagation of light?
Trả lời
(D)
diffraction patterns of light
30
The distance between the successive crests of a wave travelling at 20ms\(^{-1}\) is 25cm. Calculate the frequency of the wave
Trả lời
(D)
80.0hz
31
A ray from a fixed object is incident on a plane mirror at an angle of 20o. If the mirror is rotated through 30o by how many degree would the reflected ray rotate?
Trả lời
(A)
60o
32
Which of the following distances is usually adjustable in the camera? The distance between the
Trả lời
(A)
lens and the film
33
A travelling microscope is focused on a mark on a table. If a glass block of thickness 18.0cm is placed on the mark by how many centimeters will the microscope be moved upwards so as to focus the mark once again? [refractive index of glass = 1.5]
Trả lời
(D)
6cm
34
In which of the following media would sound wave travel fastest?
Trả lời
(C)
iron
35
Which of the following actions is necessary in order to tune a string to produce a note of an octave higher than its fundamental?
Trả lời
(B)
reducing the tension by half
36
The acceleration due o gravity may be defined as the force
Trả lời
(C)
with which the earth attracts one kilo-gram mass
37
An electron of mass m and charge \(\Box\) enters a uniform electric field between two metal plates P and q separated by a distance d. P is maintained at a potential V while Q is earthed. Determine an expression for the magnitude of the acceleration of electron through the field
Trả lời
(A)
\(\frac{eV}{md}\)
38
Which of the following factors does not affect the capacitance of a parallel plate capacitor?
Trả lời
(B)
nature of the surface of the plates
39
The equivalent capacitance of a 3\(\mu F\) capacitor and a 6\(\mu F\) capacitor connected in parallel is
Trả lời
(D)
9.0\(\mu F\)
40
a cell of e.m.f. 1.5V and internal resistance 1.0\(\Omega\) is connected to two resistor of resistance 2.0\(\Omega\) and 3.0\(\Omega\) in series. Calculate the current through the resistors
Trả lời
(A)
0.25A
41
An electric lamp rated 120W is used on a 240Vrms, calculate the resistance of its filament
Trả lời
(A)
480\(\Omega\)
42
Which of the following statements about a bar magnet is correct?
Trả lời
(D)
the magnetic properties are more pronounced at points near the end of the bar
43
The force experienced by a current-carrying conductor move in a magnetic field is employed in the working of the i. moving coil ammeter ii. electric bell iii. electric motor. Which of the statements above are correct?
Trả lời
(C)
i and iii only
44
The breaking up of an atomic nucleus into the fragment of nearly equal size is known as
Trả lời
(B)
nuclear fission
45
A 500kV is applied across an X-ray tube. Calculate the maximum velocity of the electrons produced [Me = 9.1 x 10-31kg, e = 1.6 x 10-19C]
