Two cars moving in the same direction have speeds of 100 kmh-1 and 130 kmh-1 what is the velocity of the faster car as measured by an observer in the slower car?
คำตอบ
(A)
30 kmh-1
2
A stone and a feather are dropped from the same height above the earth surface. Ignoring air resistance, which of the following is correct?
คำตอบ
(B)
the stone and the feather will both reach the ground at the same time
3
A car moves with an initial velocity of 25 ms-1 and reaches a velocity of 45 ms-1 in 10s. what is the acceleration of the car?
คำตอบ
(A)
2 ms-2
4
The surfaces of conveyor belts are made rough so as to?
คำตอบ
(B)
prevent the loads from slipping
5
A machine of velocity ratio 6 requires an effort of 400 N to raise a load of 800 N through I m. Find the efficiency of the machine
คำตอบ
(C)
33.3%
6
If a wire 30 cm long is extended to 30.5 cm by a force of 300 N. find the strain energy of wire
คำตอบ
(A)
0.75 J
7
In a hydraulic press, the pump piston exerts a pressure of 100 pa on the liquid. what force is exerted in the second piston of cross sectional area 3 m2?
คำตอบ
(A)
300 N
8
The accurate measurement of the relative density of a substance in its powdered form is done with a beam balance and?
คำตอบ
(A)
a density bottle
9
A hydrometer is an instrument used in measuring?
คำตอบ
(D)
relative density of a liquid
10
One special advantage of alcohol over mercury as a thermometric liquid is its?
คำตอบ
(B)
low freezing point
11
The density of a certain oil on frying becomes 0.4 kgm\(^{-3}\) with the volume of 20m\(^{3}\). what will be its initial volume when its initial density is 0.8 kgm\(^{-3}\) assuming no loss of oil due to spillage?
คำตอบ
(B)
10m3
12
Heat is radiated by hot objects in the form?
คำตอบ
(C)
infrared rays
13
If a container is filled with ice to the brim, what happens to the level of water when the ice completely melts?
คำตอบ
(D)
the level of water drops
14
The small droplet of water that forms on the grass in the early hours of the morning is
คำตอบ
(B)
dew
15
A vapor is said to be saturated when?
คำตอบ
(A)
a dynamic equilibrium exists between liquid molecules and the vapour molecules
16
The pressure of one mole of an ideal gas of volume 10-2 m3 at a temperature of 27°c is
[molar gas constant = 8.3 J mol-1 k-1]
คำตอบ
(C)
2.49 x 105 Nm-2
17
Which of the following has no effect on radiation?
คำตอบ
(B)
density
18
The wavelength of a wave traveling with a velocity of 420 ms-1 is 42 m. what is its period?
คำตอบ
(D)
0.1 s
19
The sound of an electricity bell dies down slowly when air is slowly pumped out from a bottle because
คำตอบ
(C)
sound needs a material medium
20
During a thunderstorm, the sound is heard over a long time. this phenomenon is referred to as?
คำตอบ
(D)
reveraberation
21
In comparing the camera and the human eye, the film of the camera function as the?
คำตอบ
(A)
retina
22
An object 4 cm high is placed 15 cm from a concave mirror of focal length 5 cm. The size of the image is?
คำตอบ
(A)
2 cm
23
An object is embedded in a block of ice, 10 cm below the plane surface. if the refractive index of the ice is 1.50, the apparent depth below the surface is?
คำตอบ
(B)
6.67 cm
24
Which of the following is used for the correction of short sightedness?
คำตอบ
(B)
concave lens
25
Dispersion occurs when white light passes through a glass prism because of the?
คำตอบ
(B)
different speeds of the colour in the glass
26
When a positively charged rod is brought nearer the cap of a positively charged electroscope, the leaves divergence will?
คำตอบ
(C)
diverge
27
Power supply is transmitted at a very high voltage and low current in order to?
คำตอบ
(D)
prevent overheating of the coil
28
A galvanometer with full-scale deflection of 10 mA is to be converted to a voltmeter with full-scale deflection of 5v. if a series resistance of 498Ω is used for the conversion, the resistance of the galvanometer is ?
คำตอบ
(B)
2Ω
29
Two inductors of inductance 5 mll and 15 mll are connected in series and a current of 5A flows through them. the total energy stored in the inductor is?
คำตอบ
(E)
no correct option
30
In alternating current circuit at resonance, the angle of lead or lag is?
คำตอบ
(D)
0°
31
In a discharge tube, most of the gas is pumped out so that electricity is conducted at?
คำตอบ
(D)
low pressure
32
The ground stated energy for the hydrogen atom is 5.44 x 10-19J . If an electron drops from zero energy to ground state, calculate the frequency of the emitted radiation?
[h = 6.6 x 10-34 Js]
คำตอบ
(E)
No correct option
33
Transistors are used for the?
คำตอบ
(C)
amplification of signals
34
Which of the following is a pure semiconductor?
คำตอบ
(B)
silicon
35
The diagram above shows a velocity - time graph. The statement that is true about this motion is that the car?
คำตอบ
(A)
has no acceleration between point F and G
36
The diagram above represents balls in an undulating surface. Which of the following option represents positions of stable equilibrium?
คำตอบ
(C)
III, VI and IX
37
A bob of weight 0.1 N hangs from a massless string of length 50 cm. A variable horizontal force which increase from zero is applied to pull the bob until the string makes an angle of 60o with the vertical. The work done is?
คำตอบ
(D)
0.025 J
38
Two metals P and Q of length l1 and l2 are heated through the same temperature difference. If the ratio of the linear expansivities of P to Q is 2:3 and the ratio of lengths is 3:4. What is the ratio of increase in length of P to Q?
คำตอบ
(C)
1:2
39
THe velocity of sound in air at 16oC is 340ms-1. What will it be when the pressure is doubled and its temperature raised to 127ºC?
คำตอบ
(A)
400 ms-1
40
Three capacitors of capacitance 2μF, 4μFand 8μF are connected in parallel and a P.D of 6V is maintained across each capacitor, the total energy stored is?
คำตอบ
(C)
2.52 x 10-4J
41
A cell of e.m.f 12V and internal resistance 4Ω is connected to an external resistor of resistance 2Ω. Find the current flow.
คำตอบ
(D)
2 A
42
The diagram above shows a balanced metre bridge, the value of x is
คำตอบ
(C)
33.3 cm
43
Three 4Ω resistors connected in parallel have a potential difference of 16 V applied across them. What is the total current in the circuit?
คำตอบ
(B)
12 A
44
In the diagram above, a 200 W bulb is lighted by a 240 V a.c mains supply. If 1kwh is sold at N40, the cost of keeping the bulb lighted for a day is?
คำตอบ
(B)
N192.00
45
In the diagram above, if the south-poles of two magnets strokes steel bar, the polarities at T and V will respectively be
