An object of mass 0.40 kg attached to the end of a string is whirled around in a horizontal circle of radius 2.0m with a constant speed of 8\(ms^{-1}\). Calculate the angular velocity of the object
Απάντηση
(C)
4 rad\(s^{-1}\)
2
An object falls freely from a height of 25m onto the roof a building 5m high. Calculate the velocity with which the object strikes the roof (g=10\(ms^{-2}\)
Απάντηση
(B)
20\(ms^{-2}\)
3
A ball of mass 0.1kg approaching a tennis player with a velocity of 10ms\(^{-1}\),is hit back in the opposite direction with a velocity of 15ms\(^{-1}\). If the time of impact between the racket and the ball is 0.01s, calculate the magnitude of the force with which the ball is hit
Απάντηση
(C)
250N
4
Two blocks of the same dimension, one steel and the other wooden are dropped simultaneously from the same height. If they fall freely neglecting air resistance the?
Απάντηση
(A)
Two blocks hit the ground simultaneously because they have the same acceleration
5
Two forces 3N and 4N act on a body in directions due north and due east respectively. Calculate their equilibrant
Απάντηση
(C)
5N 37° north of east
6
A missile weighing 400N on the earth surface is shot into the atmosphere to an altitude of 6.4 x \(10^{-6}\)m. Taking the earth as a sphere of radius 6.4 x \(10^{-6}\)m and assuming the inverse-square law of universal gravitation, what would be the weight of the missile at that altitude?
Απάντηση
(A)
100N
7
A solid plastic cube of side 0.2m is submerged in a liquid density of 0.8kg\(m^{-3}\). Calculate the upthrust of the liquid on the cube (g=10\(ms^{-2}\)
Απάντηση
(A)
0.064N
8
A piece of copper of mass 30g loses 60J of heat energy. If the specific heat capacity of copper is 400J\(kg^{-1}K^{-1}\), Calculate the change in the temperature of the copper
Απάντηση
(E)
5K
9
Steel bars each of length 3m at 28°C are to be used for constructing a rail line. If the linear expansitivity of the steel is 1 x \(10^{-5}K^{-1}\),what is the safety gap that must be left between the successive bars if the highest temperature expected is 40°C?
Απάντηση
(D)
3.6x\(10^{-2}cm\)
10
Which of the following explains why a thick glass cup cracks when boiling water is poured into it?
Απάντηση
(A)
Unequal expansion of the exterior and interior walls of the cup
11
When white light is incident on a glass prism the spectrum produced on a screen placed beyond the prism is due to?
Απάντηση
(C)
Refraction
12
At what distance from a simple microscope must an object be placed so that the image 5 times the size of the object is produced 20cm from the lens?
Απάντηση
(C)
4cm
13
Whenever light waves are restricted to a specific plane they are said to be
Απάντηση
(E)
Plane polarized
14
A solid material of volume 100\(cm^{-3}\) is heated through a temperature difference of 40°C. Calculate the increase in the volume of the material if its linear expansitivity is 2 x \(10^{-6}K{-1}\)
Απάντηση
(A)
2.4 x\(10^{-2}cm^{-3}\)
15
Calculate the quantity of heat released when 100g of steam at 100°C condenses to water(Take the specific latent heat of vaporization of water as 2.3x \(10^6Jkg^{-1}\))
Απάντηση
(D)
2.3x\(10^{5}J\)
16
A fixed mass of gas occupies a volume of 20\(cm^3\) at a fixed pressure of 700mmHg. Assuming that the temperature remains constant, what will be the volume of the gas at 750mmHg?
Απάντηση
(C)
18.7\(cm^3\)
17
A converging lens of focal length 15cm is used to obtain a real image magnified \(1\frac{1}{2}\) times. Calculate the distance of the image from the lens?
Απάντηση
(A)
37.5cm
18
A cup containing 100g of pure water at 20°C is placed in a refrigerator. If the refrigerator extracts heat at a rate of 840J per minute, calculate the time taken for the water to freeze. Neglect the heat capacity of the material of the cup. (Specific heat capacity of water =4.2J\(g^{-1}K^{-2}\))((Specific latent heat fusion of water =336J\(g^{-1}\)
Απάντηση
(D)
50 minutes
19
What is the frequency of a radio wave of wavelength 150m if the velocity of radio waves in free space is 3 x \(10^8ms^{-1}\)?
Απάντηση
(E)
2 x \(10^{6}Hz\)
20
Which of the following statements about kinetic theory of matter is not correct?
Απάντηση
(B)
When a body is heated the average kinetic energy of its molecules decreases
21
Which of the following is not correct about the Rutherford’s model of an atom?
Απάντηση
(D)
The model is applicable to atoms with only one electron in the outer shell
22
The ratio of tensile stress to tensile strain is known as
Απάντηση
(E)
Young’s modulus
23
Which of the following statements is not true of nuclear fission?
Απάντηση
(C)
Two light nuclei are made to combine to form a heavy nucleus
24
When a paint brush is removed from clean water, the bristles of the brush are pulled together because of
Απάντηση
(C)
Surface tension forces
25
The half-life of a radioactive material is 6hrs. What quantity of 1kg of the material would decay in 24 hours?
Απάντηση
(A)
\(\frac{15}{16}\)kg
26
The odor of a leaking gas is perceived at a distance from the source. This is made possible by the process of
Απάντηση
(B)
Diffusion
27
Lenz’s law of electromagnetic induction is essentially a statement of the
Απάντηση
(E)
Law of conservation of energy
28
The relationship between the directions of magnetic field, the current-carrying wire in the field is easily remembered using
Απάντηση
(B)
Right hand grip rule
29
The current in the primary coil of a transformer is 2.5A. If the coil has 50 turns and the secondary250 turns, calculate the current in the secondary coil. Neglect energy losses in the transformer
Απάντηση
(B)
0.5A
30
In a photocell, light energy is converted to
Απάντηση
(A)
Electrical energy
31
Two identical waves traveling in the same direction are superimposed. What should be the phase difference between the waves for maximum destructive interference to occur?
Απάντηση
(C)
180°
32
When a resistor of resistance R is connected across a cell, the terminal p.d of the cell is reduced to three quarters of its e.m.f. The internal resistance of the cell is expressed as
Απάντηση
(B)
R/3
33
A pipe open at both ends, produces a fundamental note. If the velocity of sound in air is V and L the length of the pipe, which of the following expresses the frequency of the note? Neglect end correction
Απάντηση
(B)
V/2L
34
Which of the following statements is not correct?
Απάντηση
(E)
Wind speed effects on the speed of sound in air
35
A progressive wave has a wavelength of 50cm. calculate the phase difference between two points at a distance of 20cm apart.
Απάντηση
(C)
4/5 π
36
An alternating current with a peak value of 5A passes through a resistor of resistance 10Ω. Calculate the rate at which energy is dissipated in the resistor
Απάντηση
(B)
125W
37
The invisible part of the spectrum of a white light consists of the following colors
Απάντηση
(E)
Ultra violet and infra-red only
38
Which of the following is not true of the similarities between a camera and the human eye?
Απάντηση
(D)
The distance between the lens and the screen is fixed in both
39
The magnification produced with a converging lens is 5. If the object is a square wire gauze of side 2cm, calculate the area of the image
Απάντηση
(C)
20\(cm^3\)
40
A magnet is being inserted into a coil of wire. On which of the following factors does the induced e.m.f in the coil depend? I. Number of turns in the coil II. Strength of the coil III. Speed with which magnet is inserted into the coil.
Απάντηση
(E)
I, II,III only
41
The current in a series R-L-C circuit attains its maximum value when the
Απάντηση
(B)
Inductive reactance is equal to the capacitive reactance
42
A charge of 1 x \(10^{-5}\)C experiences a force of 40N at a certain point in space. What is the magnitude of the electric field intensity at the point in Newton and couloumb
Απάντηση
(B)
4 x \(10^{6}\)
43
A capacitor of capacitance 25µF is connected to an a.c power source of frequency 200/πHz. Calculate the reactance of the capacitor
Απάντηση
(D)
100Ω
44
During the electrolysis of copper (II) tetraoxosulphate (VI) solution, an ammeter shows a steady reading of 1A for 30minutes while 6.6 x \(10^{-4}\)kg of copper is liberated. Calculate the error in the ammeter The electrochemical equivalent of copper is 3.30 x \(10^{-7}kgC{-1}\)
Απάντηση
(C)
0.111A
45
In a nuclear reaction, the mass defect is 2 x \(10^{-6}\)g. Calculate the energy released given that the velocity of light is 3 x \(10^{8}ms^{-1}\)
