What is the least possible error encountered when taking measurement with a meter rule?
คำตอบ
(C)
0.5mm
2
A quantity which requires magnitude and direction to be specified is
คำตอบ
(C)
Displacement
3
I Electrical potential, II Torque, III Kinetic Energy, IV Momentum. Which of the quantities listed are vectors?
คำตอบ
(A)
II and IV
4
Which type of motion do the wheels of a moving car undergo?
คำตอบ
(D)
Translational and rotational motion
5
A car accelerates uniformly from rest at 3ms-2. its velocity after traveling a distance of 24m is
คำตอบ
(A)
12ms-1
6
Calculate the escape velocity of a satellite launched from the earth's surface if the radius of the earth is 6.4x106m
คำตอบ
(D)
11.3kms-1
7
An object of weight 8kg on earth is taken to a planet where acceleration due to gravity is one-third of its value on earth. The weight of the object on the planet is
คำตอบ
(C)
27N
8
One of the conditions necessary for an object to be in equilibrium when acted upon by a number of parallel forces is that the vector sum of the forces is
คำตอบ
(B)
Zero
9
What happens when three coplanar non-parallel forces are in equilibrium?
คำตอบ
(D)
Their lines of action meet at a point
10
An object of mass 20kg is released from a height of 10m above the ground level. The kinetic energy of the object just before it hits the ground is
คำตอบ
(C)
2000J
11
The energy in the nucleus of atoms produce heat which can be used to generate
คำตอบ
(C)
Electrical energy
12
A machine whose efficiency is 75% is used to lift a load of 1000N. Calculate the effort put in to the machine if it has a Velocity ratio of 4.
คำตอบ
(C)
333.33N
13
A wheel and an axle is used to raise a load whose weight is 800N when an effort of 250N is applied. If the radii of the wheel and axle are 800mm and 200mm respectively, the efficiency of the machine is
คำตอบ
(B)
80%
14
A force of 500N1 is applied to a steel wire of cross-sectional area 0.2m2, The tensile stress is
คำตอบ
(D)
2.5x103Nm-2
15
The small droplets of water that form on the grass in the early hours of the morning is
คำตอบ
(D)
Dew
16
What is the equivalent of 20K in Celsius scale?
คำตอบ
(A)
-253oC
17
The equation PaVbTc= constant reduces to Charles Law if
คำตอบ
(D)
a=0, b=1 and c=-1
18
The quantity of heat needed to raise the temperature of a body by 1K is the body's
คำตอบ
(A)
Heat capacity
19
The melting point of a substance is equivalent to its
คำตอบ
(B)
Solidification Temperature
20
The temperature at which the water vapour present in the air is just sufficient to saturate air is
คำตอบ
(D)
Dew point
21
Heat transfer by convection in a liquid is due to the
คำตอบ
(D)
Expansion of the liquid as it is heated
22
The distance between two successive crests of a wave is 15cm and the velocity 300ms-1. Calculate the frequency.
คำตอบ
(C)
2.0x103Hz
23
A boy receives the echo of his clap reflected by a nearby hill 0.8s later. How far is he from the hill? [ speed of sound in air = \(340ms^{-1}\)
คำตอบ
(C)
136m
24
An object is placed 10m from a pinhole camera of length 25cm. Calculate the linear magnification.
คำตอบ
(B)
2.5x10-2
25
The focal length of a concave mirror is 2.0cm. If an object is placed 8.0cm from it, the image is at
คำตอบ
(A)
2.7m
26
In a compound microscope, the objective and the eye piece focal lengths are
คำตอบ
(C)
Short
27
When a telescope is in normal use, the final image is at
คำตอบ
(A)
Infinity
28
When a negatively charged rod is brought near the cap of a charged gold leaf electroscope which has positive charges, the leaf
คำตอบ
(B)
Collapses
29
What charge is stored in a 0.1F capacitor when a 10V supply is connected across it?
คำตอบ
(A)
1C
30
The maximum power transfer occur in a cell when the external resistance is
คำตอบ
(B)
The same as the internal resistance of the cell
31
A circuit has a resistance of 200Ω. The resistance of the circuit can be reduced to 120Ω when
คำตอบ
(A)
A 300Ω resistor is connected to it in parallel
32
PHCN measures its electrical energy in
คำตอบ
(B)
KWh
33
What is the best method of demagnetizing a steel bar magnet?
คำตอบ
(D)
Solenoid method
34
The magnitude of the angle of dip at the equator is
คำตอบ
(B)
0o
35
When an atom undergoes a beta decay, the atomic number of the nucleus
คำตอบ
(C)
Increases by one
36
Calculate the mass of the copper deposited during electrolysis when a current of 4A passes through a copper salt for 2 hours. [Ece of Copper z=3.3x10-7kgC-1]
คำตอบ
(C)
9.5x10-3kg
37
Which gas produces a red coloured light in a discharge tube?
คำตอบ
(D)
Neon
38
Which of the following is NOT a Fundamental S.I unit?
คำตอบ
(C)
Newton
39
When \(^{210}_{82}Pb\) decays to \(^{206}_{80}Pb\), it emits
คำตอบ
(B)
an alpha particle
40
What type of reaction is represented by the equation \(^{2}_{1}X+^{2}_{1}X\rightarrow^{3}_{2}Y+^{1}_{0}n+Energy\)
