Which of the following phenomena is the practical evidence for the existence of the continual motion of molecules?
Απάντηση
(C)
brownian motion
2
Each of the following physical quantities is classified as a vector or a scalar quantity. Which of the classifications is correct?
Απάντηση
(D)
magnetic flux density (vector)
3
Which of the following statements about a spring balance and/or a chemical balance is not correct?
Απάντηση
(C)
either may be used to measure the weight of a substance
4
The friction which exists between two layers of liquid in relative motion is called
Απάντηση
(C)
viscosity
5
A body of mass 25kg, moving at 3ms-1 on a rough horizontal floor is at rest after sliding through a distance of 2.50m on the floor. Calculate the co-efficient of sliding friction. [g = 10.0ms-2]
Απάντηση
(B)
0.18
6
Which of the following simple machines is a second class lever?
Απάντηση
(A)
wheel barrow
7
A wheel and axle of radii 800mm and 200mm respectively is used to raise a body of weight 800N by the application of 250N. Calculate the efficiency of the machine
Απάντηση
(B)
80%
8
Masses,m1 and m2 at the 20-cm and 65-cm marks respectively of a uniform metre rule freely suspended at its centre of gravity. If the metre rule balances horizontally, determine the ratio m2 : m1
Απάντηση
(D)
1 : 2
9
Which of the following type of motion does a body undergo when acted upon by a couple?V
Απάντηση
(C)
rotational
10
A body starts from rest and accelerates uniformly at 5ms^-2 until it attains a velocity of 25ms-1. Calculate the time taken to attain this velocity
Απάντηση
(B)
5.0s
11
The frequency of a swinging pendulum is the
Απάντηση
(A)
number of complete oscillations the pendulum makes in a second
12
Which of the following about an object performing simple harmonic motion is correct? Its acceleration
Απάντηση
(A)
is maximum at the extreme ends
13
A body of mass 5kg moving with a velocity of 10ms-1 collides with a stationary body of mass 6kg. If the two bodies stick together and move in the same direction after their collision, calculate their common velocity
Απάντηση
(A)
4.55ms-1
14
Fuel was consumed at a steady rate of 5.0 x 10-2kg per second in a rocket engine and ejected as a gas with a speed of 4 x 103ms-1. Determine the thrust on the rocket
Απάντηση
(C)
200N
15
Which of the following quantities has the same unit as energy?
Απάντηση
(B)
work
16
Which of the following source of energy is renewable?
Απάντηση
(A)
sun
17
The lower and upper fixed point of a thermometer are 30mm and 180mm respectively. Calculate the temperature in degrees Celsius when the thermometer reads 45mm
Απάντηση
(A)
10.0oC
18
A body of mass m, has a specific heat capacity s, and a heat capacity c. If the temperature of the body changes by \(\theta^oC\), Which of the following equation is correct?
Απάντηση
(B)
ms = C
19
An immersion heater rated 400W, 220V is used to heat a liquid of mass 0.5kg. If the temperature of the liquid increases uniformly at the rate of 2.5oC per second, calculate the specific heat capacity of the liquid. [Assume no heat is lost]
Απάντηση
(B)
320Jkg-1K-1
20
Water falls through a height of 50m. Determine the temperature rise at the bottom of the fall. [Neglect energy losses. Specific heat capacity of water = 4200Jkg-1 K-1, g = 10ms2]
Απάντηση
(A)
0.119oC
21
The energy required to change a solid to liquid at constant temperature is called
Απάντηση
(C)
latent heat of fusion
22
Which of the following statements about boiling and evaporation at atmospheric pressure is correct?
Απάντηση
(D)
boiling takes place at 100o while evaporation my take place at temperatures lower than 100oC
23
Which of the following statements is correct?
Απάντηση
(A)
the density of a liquid decreases when it expands
24
The pressure exerted by a given mass of gas in a container
Απάντηση
(B)
increases if the molecules of the gas move faster
25
Which of the following statements about a progressive mechanical wave is correct?
Απάντηση
(D)
its frequency remains constant as it travels between different media
26
The distance between two points in phase on a progressive wave is 5cm. If the sped of the wave is 0.2ms-1, calculate its period
Απάντηση
(C)
0.25s
27
Radio waves travel in air at 3.0 x 108ms-1. If the waves enter water of refractive index \(\frac{4}{3}\), calculate the speed of radio waves in water
Απάντηση
(C)
2.25 x 108ms-1
28
The amplitude of a wave is the
Απάντηση
(B)
maximum diplacement of the wave particle from the equilibrum position
29
Which of the following optical instruments does not depend on the use of plane mirrors?
Απάντηση
(B)
simple microscope
30
A ray of light is incident normally on a plan mirror. If the incident ray is kept fixed while the mirror is rotated through an angle of 30o, determine the initial and final angles of reflection respectively
Απάντηση
(D)
90o and 60o
31
In which of the following media is the transmission of sound wave fastest?
Απάντηση
(D)
Iron
32
The ability of a material to store an electric charge when its plates are at different potentials is referred to as its
Απάντηση
(C)
capacitance
33
Two capacitors if capacitance 0.4\(\mu F\) and 0.5\(\mu F\) are connected in parallel and charged to a p.d. of 50V, Determine the total charge acquired
Απάντηση
(A)
45\(\mu C\)
34
A parallel plate capacitor of capacitance 600\(\mu F\) has a potential difference of 200V between its plates. Calculate the charge on either plate of the capacitor
Απάντηση
(A)
1.2C
35
A parallel plate capacitor of capacitance 600\(\mu F\) has a potential difference of 200V between its plates. Calculate the charge on either plate of the capacitor
Απάντηση
(A)
1.2C
36
a chemical cell of internal resistance 1\(\Omega\) supplies electric current to an external resistor of resistance 3\(\Omega\). Calculate the efficiency of the cell
Απάντηση
(A)
75%
37
An electric lamp is rated 240V, 40W. What is the cost of running the lamp for 72 hours if the electricity authority charges N2.50 per kWh?
Απάντηση
(A)
N7.20
38
Which of the following statements explains lost volt in an electric circuit? The
Απάντηση
(D)
p.d across the internal resistance of the cell
39
A constantan wire has a cross sectional area of 4 x 10-8m2 and a resistivity of 1.1 x 10-6\(\Omega\)m. If a resistor of resistance 11\(\Omega\) is to be made from this wire, calculate the length of the wire required
Απάντηση
(A)
0.4m
40
The mass and weight of a body on earth are 8kg and 80N respectively. Determine the mass and weight of the body respectively on a planet where the pull of gravity is \(\frac{1}{8}\) that on earth
Απάντηση
(D)
8kg, 10N
41
Lenz's law of electromagnetic induction states that
Απάντηση
(D)
the induced current in a coil is in such a direction that it sets up a magnetic field which opposes the change producing it
42
A bar magnet is placed near and lying along the axis of a solenoid connected to a galvanometer. The pointer of the galvanometer shows no deflection when
Απάντηση
(D)
there is no relative motion between the magnet and the solenoid
43
an electric motor is a machine that converts
Απάντηση
(B)
electrical energy into mechanical energy
44
Which of the following statements is an advantage of nuclear fusion over nuclear fission?
Απάντηση
(A)
The resulting chain reaction which produces large amount of energy
45
Which of the following statements is not a reason for using soft iron in making the core of a transformer? It
