A uniform solid cube material 10cm on each side of mass 700g is submerged in water. which of the following best described the behavior of the cube water?
Απάντηση
(B)
the cube will float
2
At low humidity in an environment, the human skin is usually?
Απάντηση
(C)
dry and rough
3
If the relative density of gold is 19.2, the volume of 2.4kg of gold is?
Απάντηση
(B)
1.25 x 10-4 m3
4
The thermometric property of a constant volume thermometer is?
Απάντηση
(C)
change in pressure
5
An immersion heater rated 2.0A, 240V is used to boil water from temperature 52°c to 100°c. If the mass of the water is 2.5kg. determine the time taken to boil the water.
[specific heat capacity of water = 4.2 x 103 jkg-1 k-1]
Απάντηση
(A)
1.05 x 103s
6
The thermos flask is designed to?
Απάντηση
(A)
prevent heat loss or gain by conduction, convection and radiation
7
what is likely to happen if the glass of a thermometer expands more upon heating than the liquid inside?
Απάντηση
(D)
the liquid will go down in the stem
8
A drop of petrol makes a finger colder than a drop of water would because?
Απάντηση
(A)
petrol takes its latent heat of veporization from the finger
9
A cell of internal resistance r is connected to an external resistor R. The condition for maximum power transfer is?
Απάντηση
(B)
R = r
10
The production and type of charge of a body can only be accounted for by the?
Απάντηση
(A)
deficiency or surplus of electrons
11
The main purpose of the transformer in an a.c radio set is to?
Απάντηση
(D)
step down the voltage
12
An electric heater with a p.d of 240 V connected across its terminals has a total resistance of 960Ω. find the power rating of the heater.
Απάντηση
(D)
60.00W
13
If the capacitance of a capacitor is C = \(\frac{(εA)}{d}\) which of the following parameters is varied when a variable capacitors is used for tuning radio sets?
Απάντηση
(B)
area and distance.
14
When an a.c. voltage is applied to a capacitor, no power is consumed because the current
Απάντηση
(A)
leads the voltage by 90°
15
The electrolyte in the Nickei-iron (Nife) accumulator is
Απάντηση
(A)
potassium hydroxide solution
16
During electrolysis, 2.0 g of a metal is deposited using a current of 0.5 A in 3 hours. The mass of the same metal which can be deposited using a current of 1.5 A in 1 hour is?
Απάντηση
(D)
2.0 g
17
When a certain a.c supply is connected to a lamp, it lights with the same brightness as it does with a 12 V d.c battery. Then r.m.s value of the a.c supply is?
Απάντηση
(A)
12.0 V
18
An ammeter of resistance 5Ω has a full-scale deflection when a current of 50 mA flows in it. The value of the resistor required to adapt it to measure a current of 5 A is?
Απάντηση
(D)
0.05Ω
19
The motion of smoke particles from a chimney is typical of?
Απάντηση
(A)
random motion
20
In an experiment to determine terminal velocity, as the pressure increases, the viscosity off a liquid
Απάντηση
(A)
increases
21
If the radius of the earth is 6.4 x 10\(^6\)m, the escape velocity of a satellite from the earth is?
[g = 10 ms-2]
Απάντηση
(A)
1.13 x 104 ms-1
22
The component of vector X along the direction of vector Y is zero when
Απάντηση
(C)
X is perpendicular to Y
23
The correct unit of energy density is?
Απάντηση
(D)
kg m-1 s-2
24
I. Work done by load is always less than the work done by effort.
II. All machines are made of levers, pulleys, screws and gear wheels.
III. A fishing rod is a machine.
Iv. Effort is always larger than load.
which of statements above about machines are true?
Απάντηση
(C)
I and III
25
The energy associated with the emitted photon when a mercury atom changes from one state to another is 3.3 ev. calculate the frequency of the photon.
[e = 1.6 x 10-19c; h = 6.6 x 10-34js]
Απάντηση
(D)
8.0 x 1014 Hz
26
The process through which free electrons leave the surface of hot metal is known as?
Απάντηση
(C)
thermionic emission
27
The battery connection that permits current to flow across a p-n junction is called?
Απάντηση
(B)
forward baised
28
One of the properties of gamma rays is that they are?
Απάντηση
(A)
neutral
29
A radioactive element has a half life of 4 days. The fraction that has decayed in 16 days is?
Απάντηση
(A)
\(\frac{15}{16}\)
30
The theory of electronic conduction in solids, which satisfactorily explains the properties of conductors, insulators and semi-conductor,is?
Απάντηση
(D)
band theory
31
I. The number of neutrons released exceeds the number that caused the fission.
II. There is loss of mass.
III. Energy is produced.
IV. Smaller nuclei merge to form larger nuclei
which of the statement above are correct about nuclear fission?
Απάντηση
(C)
I,II and III only
32
A certain manufacturer wishes to make an n-type semiconductor. Which materials would he select for doping?
Απάντηση
(D)
arsenic and antimony
33
A p-n junction diode is used as?
Απάντηση
(D)
a rectifier in an a.c circuit
34
An object placed 10cm from a concave mirror of focal length 5cm would have its image
Απάντηση
(A)
at the centre of convature
35
A submarine is observed to rise from a real depth of 80 m to 60 m in water. Calculate the change in apparent depth.
[Refraction index of water \(\frac{4}{3}\)]
Απάντηση
(C)
15 m
36
Non-luminous object can be seen because they
Απάντηση
(A)
reflect light
37
The wavelength of the first overtone of a note in a closed pipe of length 33 cm is?
Απάντηση
(B)
44 cm
38
A person can focus objects when they lie beyond 75 cm from his eyes. The focal length of the lens required to reduce his least distance of distinct vision to 25 cm is?
Απάντηση
(A)
37.50 cm
39
A conductor has a diameter of 1.00 mm and length 2.00m. if the resistance of the material is 0.1Ω, its resistivity is?
Απάντηση
(D)
3.93 x 10-8 Ωm
40
The diagram above represents the stress-strain graph for a typical metal rod. What does the X represent?
Απάντηση
(A)
Breaking point
41
In the diagram above, the pressure of the gas is
Απάντηση
(A)
86 cm of mercury
42
A mirror of weight 75N is hung by a cord from a hook on the wall. If the cord makes an angle of 30o with horizontal, the tension in the cord is
Απάντηση
(D)
150N
43
In a gas experiment, if the volume of the gas is plotted against the reciprocal of the pressure, the unit of the slope of the resulting curve is
Απάντηση
(D)
work
44
A shooter wants to fire a bullet in such a way that its horizontal range is equal to three times its maximum height. At the what angle should he fire the bullet to achieve this?
Απάντηση
(B)
53o
45
An engine of a car of power 80 kW moves on a rough road with a velocity of 32 m\(s^-1\). The forces required to bring it to rest is
