I. Force (N)
II.Torque (Nm)
III. Current (A)
IV. Power (W)
Which of the above are the correct S. I: units of the quantities indicated?
Trả lời
(D)
I, II, III and IV only
2
Which of the following is NOT a vector quantity?
Trả lời
(A)
altitude
3
If a wheel 1.2 m in diameter rotates at one revolution per second, calculate the velocity of the wheel.
Trả lời
(B)
3.77 ms-1
4
I. All the three forces must be concurrent.
II. The upward force is equal to the downward force.
III. The algebraic sum of the moment about any point must be zero.
which of the above conditions must hold for a body acted upon by a system of three coplanar forces equilibrium?
Trả lời
(D)
I, II and III
5
What is the frequency of vibration if the balance wheel of a wrist watch makes 90 revolutions in 25 s?
Trả lời
(D)
3.60 Hz
6
If a body mass 5kg is thrown vertically upwards with velocity u,at what height will the potential energy equal to the kinetic energy?
Trả lời
(B)
h = (u)2/4g
7
counting of currency notes with moist fingers is based on the principles of?
Trả lời
(C)
adhesion
8
A motorcycle of mass 100kg moves round in a circle of radius 10m with a velocity of 5 ms-1. find the coefficient of friction between the road and the tyres.
Trả lời
(D)
0.25
9
A spring of force constant 500 NM-1 is compressed such that its length shortens by 5cm. The energy stored in the spring is?
Trả lời
(A)
0.625 J
10
In the hare's apparatus, water rises to a height of 26.5 cm in one limb. if a liquid rises to a height of 20.4 cm in the other limb, what is the relative density of the liquid?
Trả lời
(D)
1.3
11
When cold water is poured on a can containing hot water, the can collapses because the?
Trả lời
(D)
external pressure becomes greater than the pressure within the can.
12
An empty density bottle weighs 2 N. if it weighs 5 N when filled with water and 4 N when filled with olive oil, the relative density of olive oil is?
Trả lời
(B)
(2)/3
13
The thermometric properties of a thermocouple is the change in?
Trả lời
(B)
electromotive force
14
During summer, the balance wheel of a clock expands.what effect does this have on the accuracy of the clock?
Trả lời
(C)
the clock losses time
15
A sealed flask contains 600cm3 of air at 27°C and is heated to 35°C at constant pressure. The new volume is?
Trả lời
(D)
616 cm3
16
A block of aluminum is heated electrically by a 25 W heater. if the temperature rises by 10°C in 5 minutes, the heat capacity of the aluminum is?
Trả lời
(B)
750 JK-1
17
If the partial pressure of water vapour at 27°C is 18 mm Hg and the saturated vapour pressure of the atmosphere at the same temperature is 24 mm Hg, the relative humidity at this temperature is?
Trả lời
(C)
75%
18
In a good thermos flask, heat loss is reduced through the following features EXCEPT?
Trả lời
(A)
the lens surface
19
Given the progressive wave equation y = 5 sin (2000 πt - 0.4x), calculate wave length
Trả lời
(B)
15.7 m
20
The fundamental property of a propagating wave which depends only on the source and not the medium of propagation is the?
Trả lời
(C)
frequency
21
I. Total internal reflection of light.
II. Conservation of light energy.
III. Relative motion of the earth, sun and moon.
IV. Rectilinear propagation of light.
which of the above is a phenomenon of total solar eclipse?
Trả lời
(D)
III and IV only
22
An object of height 4cm is placed in front of a cuboid pinhole camera of size 6 cm. if the image formed is 2 cm high, how far is the object from the pinhole?
Trả lời
(C)
12.0 cm
23
An object of heights 5 cm is placed at 20 cm from a concave mirror of focal length 10 cm. the image height is?
Trả lời
(D)
5 cm
24
Convex mirror are used as driving mirrors because images formed are?
Trả lời
(A)
erect, virtual and diminished
25
An object placed at the bottom of a well full of clear water appears closer to the surface due to?
Trả lời
(C)
refraction
26
In the microscope, the eyepiece lens merely acts as?
Trả lời
(D)
a magnifier
27
Short sightedness can be corrected by what type of lens?
Trả lời
(A)
Concave lens
28
A short chain is sometimes attached to the back of a petrol tanker to?
Trả lời
(D)
conduct excess charges to the earth
29
An electric generator has e.m.f. of 240 V and an internal resistance of 1Ω if the current supplied by the generator is 20A when the terminal voltage is 220 V, find the ratio of the power supplied to the power dissipated?
Trả lời
(A)
11:1
30
A generator is on daily use and in the process, ten 60 W and five 40 W tungsten bulbs are on for the same time interval. the energy consumed daily is?
Trả lời
(D)
19.20 kWh
31
The d.c generator has essentially the same components as the a.c generator except the presence of?
Trả lời
(C)
split ring
32
A step-down transformer has a power output of 50 W and efficiency of 80%. if the mains supply voltage is 200 v, calculate the primary current of the transformer.
Trả lời
(A)
0.31 A
33
caesium has a work function of 3 x 10-19J. the maximum energy of liberated electrons when it is illuminated by light of frequency 6.7 x 1014
HZ is?
[h = 6.6 x 1010-34Js]
Trả lời
(A)
1.42 x 10-19J
34
zener diode is used for?
Trả lời
(C)
voltage regulation
35
When a pure semiconductor is heated, its resistance?
Trả lời
(B)
decreases
36
I. for current amplification.
II. for voltage stabilization.
III. for power amplification.
IV. as a switch.
which of the above are the uses of transistor?
Trả lời
(A)
I,II,III and IV
37
The dimension of electromotive force are?
Trả lời
(A)
ML2T-3I-1
38
The resultant of two forces 12N and 5N is 13N. What is the angle between the two forces?
Trả lời
(C)
90o
39
A force F required to keep a 5 kg mass moving round a cycle of radius 3.5 m at a speed of 7 ms-1. What is the speed, if the force is tripled?
Trả lời
(C)
12.1 ms-1
40
A body of mass 4 kg resting on a smooth horizontal plane is simultaneously acted upon by two perpendicular forces 6N and 8N. Calculate the acceleration of the motion
Trả lời
(A)
2.5 ms-1
41
The diagram above shows a plank RS pivoted its center of gravity O and is in equilibrium with the weight P and Q. If a weight 2P is added to P the plank will be in equilibrium again by?
Trả lời
(B)
moving P nearer to O
42
The efficiency of the pulley system shown above is 80%. find the effort E required to lift the load of 1200N
Trả lời
(C)
375N
43
The diagram above is the heating curve for a solid, QR is the?
Trả lời
(A)
melting region
44
The above figure shows the motion of a progressive wave along a string. The particle motion of the medium is in direction?
Trả lời
(B)
parallel to OY
45
If a concave lens of focal length 12cm is used to produce a real image four times the size of the object, how far from the lens must the object be placed?
