The area under a force-time graph represents--------
Trả lời
(B)
change in momentum
2
From the principle of flotation, a body sinks in a fluid until it displace a quantity equal to its own?
Trả lời
(C)
weight
3
The length of a simple pendulum is increased by a factor of four. By what factor is its period increase?
Trả lời
(B)
2
4
The linear expansivity, \(\alpha\), and cubic expansivity, \(\gamma\), of a material are related by the equation?
Trả lời
(B)
\(\gamma\)=3\(\alpha\)
5
Suppose three identical steel balls Q, R, and S, are placed on an undulating ground as illustrated in the diagram above. Which of the balls is/are in neutral equilibrium?
Trả lời
(C)
R only
6
Which of the illustrated graphs above represents a body moving with uniform retardation?
Trả lời
(D)
D
7
The correct relationship between the displacement, s, of a particle initially at rest in a linear motion and the time, t, is?
Trả lời
(D)
s \(\alpha\) t\(^{2}\)
8
The joule is equivalent to?
Trả lời
(C)
Kg m\(^{2}\) s\(^{-2}\)
9
Which of the following statement(s) is/are correct about a fixed mass of gas compressed in an inexpansible container;
I. The average speed of the molecules increases
II. The temperature of the gas increases
III. The molecules hit the walls of the container more often than before the compression
Trả lời
(C)
I, II, and III only
10
An example of a mechanical wave is---------
Trả lời
(A)
water waves
11
Which of the following descriptions of the image formed by a plane mirror is not correct. the image is----
Trả lời
(C)
erect and bigger than the object
12
The efficiency of a wheel and axle is 100% and the ratio of their radii is 5:1. calculate the effort required to lift a load of mass 20kg using this machine, [g = 10 m s\(^{-2}\)]
Trả lời
(C)
40N
13
A freely suspended compass needle on the earth's surface settles in a plane called----------
Trả lời
(B)
magnetic meridian
14
An object is placed at different distances, u, from a converging lens of focal length, 15.0cm. For what value of u does the lens act as a microscope?
Trả lời
(C)
M < 15cm only
15
The periodic rise and fall in the intensity of sound produced whn two notes of nearly equal frequencies are sounded together is called?
Trả lời
(B)
beat
16
The power of the lens is +2.5D. What is the radius of the curvature?
Trả lời
(D)
80.0 cm
17
The reason for having a large number of turns in the coil of a moving coil galvanometer is to--------
Trả lời
(B)
increase the sensitivity of the galvanometer
18
Current is passed through two parallel conductors in the same direction. If the conductors are placed near each other, they will------------------
Trả lời
(D)
attract each other
19
The period of a 10 kHz radio wave traveling at 10\(^{8}\) ms\(^{-1}\) is--
Trả lời
(B)
1.0 x 10\(^{-4}\) s
20
The magnetic material produced from the chemical combination of metal oxides and has a very high resistance to electric current is called
Trả lời
(A)
ferrite substance
21
A body of mass, M, moving with velocity, V, has a wavelength, X, associated with it. This phenomenon is called----------
Trả lời
(D)
wave-particles paradox
22
Which of the following statements about a straight current-carrying wire placed in a uniform magnetic field is correct? The wire experiences ---------------
Trả lời
(B)
no motor force of it is parallel to the field
23
Three cells each of emf, 1.0 V, and internal resistance, 2 \(\Omega\), are connected in parallel across a 3\(\Omega\) resistor. Determine the current in the resistor.
Trả lời
(C)
0.30A
24
Which of the following statements about electric potential energy is not correct?
Trả lời
(C)
The electric potential energy of a positively charged particle decreases when it moves to a point of higher potential
25
A galvanometer with a full-scale deflection of 20 mA is Converted to read 8 K by connecting a 395 \(\Omega\) resistor in series with it. Determine the internal resistance of the galvanometer
Trả lời
(B)
5.0\(\Omega\)
26
.An inductor of inductance 10 H is connected across an a.c circuit source of 50 V, 100 Hz. What is the current in the circuit? [\(\pi\) = 3.14]
Trả lời
(D)
0.008A
27
The speed of fast-moving neutrons in a nuclear reactor can be reduced by using?
Trả lời
(A)
graphite rods
28
In a series R-L-C circuit at resonance, impedance is----
Trả lời
(B)
minimum
29
A lamp is rated 240 V, 60 W. Determine the resistance of the lamp when lit?
Trả lời
(D)
960\(\Omega\)
30
One major reason why electrical appliances in homes are normally earthed is that the-----------
Trả lời
(A)
person touching the appliance is safe from electric shock
31
In doping an intrinsic semiconductor to produce a p-type semiconductor,
Trả lời
(C)
an acceptor element is added
32
Arrange the following radiations in order of increasing ionization of air.
I. Alpha
Il. Gamma
IIl. Beta
Trả lời
(C)
II < III < I
33
If the kinetic energy of an electron is 100 eV, what is the wavelength of the de-Broglie wave associated with it? [h = 6.6 x 10\(^{-34}\) J s, e = 1.6 x 10\(^{-19}\)C, m\(_{e}\), = 9.1 x 10\(^{-31}\) kg]
Trả lời
(A)
1.22 x 10\(^{-10}\)m
34
Gamma rays are produced when?
Trả lời
(B)
energy changes occur within the nuclei of atoms
35
The half-life of a radioactive substance is 15 hours. If at some instance, the sample has a mass of 512 g, calculate the time it will take \(\frac{7}{8}\) of the sample to decay
Trả lời
(C)
45 hours
36
When the direction of vibration of the particles of a medium is perpendicular to the direction of propagation of a wave, the wave is said to be--------
Trả lời
(B)
transverse
37
A hunter fires a gun at a point 408 m away from a cliff. If he hears an echo 2.4 s later, determine the speed of the sound wave
Trả lời
(A)
340 ms\(^{-1}\)
38
The distance between the fixed points of a mercury-in-glass thermometer is 30 cm. Determine the temperature when the mercury level is 10.5 cm above the lower fixed point
Trả lời
(C)
35.0 ºC
39
Which of the following statements-about electromagnetic waves is not correct?
Trả lời
(C)
They are longitudinal
40
The diameter of a brass ring at 30 °C is 50.0 cm. To what temperature must this ring be heated to increase its diameter to 50.29 cm? [ linear expansivity of brass = 1.9 x 10\(^{-5}\) K\(^{-1}\)]
Trả lời
(D)
335.3 °C
41
Which of the following concepts is a method of heat transfer that does not require a material medium?
Trả lời
(D)
Radiation
42
Which of the folowing statements about light travelling from one material medium to another is not correct?
Trả lời
(D)
Its frequency changes.
43
The engine of a car provides a forward force of 1240 N and the total resistive force on the car is 800N. If the mass of the car is 1220 kg, determine the distance the car has to travel from the rest before acquiring a speed of 4 m s\(^{-1}\).
Trả lời
(B)
22.2 m
44
A quantity of water at 0 °C is heated to 30 °C. For each degree rise in temperature, its density will---------
Trả lời
(D)
rise and then falls
45
A small object of mass 50 g is released from a point A. Determine the velocity of the object when it reaches a point B, a vertical distance of 30m below A. [g = 10 ms\(^{-2}\)
