When a brick is taken from the earth's surface to the moon, its mass
Trả lời
(A)
remains constant
2
The resultant of two forces is 50N. If the forces are perpendicular to each other and one of them makes an angle 0f 30o with the resultant, find its magnitude.
Trả lời
(C)
43.3N
3
The pair of physical quantities that are scalar only are ?
Trả lời
(A)
volume and area
4
A simple pendulum of length 0.4m has a period of 2s. What is the period a similar pendulum of length 0.8m at the same place?
Trả lời
(C)
2\(\sqrt{2}s\)
5
A train with an initial velocity of 20ms-1 is subjected to a uniform deceleration of 2m-2. The time required to bring the train to a complete halt is?
Trả lời
(B)
10s
6
Calculate the apparent weight loss of a man weighing 70kg in an elevator moving downwards with an acceleration of 1.5ms-2.
[g = 10ms-2]
Trả lời
(D)
105N
7
A piece of cork floats in a liquid. What fraction of its volume will be immersed in the liquid?
[Density of the cork = 0.25 x 103kgm-3, Density of the liquid = 1.25 x 103kgm-3]
Trả lời
(C)
0.2
8
An object is moving with a velocity of 5m-1. At what height must a similar body be situated to have a potential energy equal in value with kinetic energy of the moving body?
Trả lời
(C)
1.3m
9
If a pump is capable of lifting 5000kg of water through a vertical height of 60m in 15 min, the power of the pump is
Trả lời
(C)
3.3 x 103js-1
10
Calculate the work done when a force of 20N stretches a spring by 50mm.
Trả lời
(A)
0.5J
11
What volume of alcohol will have same mass as 4.2m-3 of petrol?
Density of alcohol = 8.4 x 10^2 kgm-3, density of petrol =7.2x10^2 kgm-3
Trả lời
(C)
3.6m3
12
Calculate the length which corresponds to a temperature of 20oC if the ice and steam points of an unguarded thermometer are 400 mm apart
Trả lời
(D)
80mm
13
A wire of length 100.0m at 30o has linear expansive of 2x10-5K-1 Calculate the length of the wire at a temperature of - 10oC
Trả lời
(D)
99.92m
14
A gas at a pressure of 105Nm-2expands from 0.6m-3 to 1.2m3 at constant temperature, the work done is
Trả lời
(D)
6.0 x 10 4J
15
Two liquids X and Y having the same mass are supplied with the same quantity of heat. If the temperature rise in X is twice that of Y, the ratio of specific heat capacity of X to that of Y is
Trả lời
(B)
1:2
16
Steam from boiling water causes more damage on the skin than does boiling water because
Trả lời
(D)
steam brings heat more easily by convection
17
What will happen to the boiling point of pure water when it is heated in a place 30m below sea level?
Trả lời
(A)
It will be more than 100 oC
18
The rise or fall of a liquid in a narrow tube is because of the
Trả lời
(B)
surface tension of the liquid
19
The mechanism of heat transfer from one point to another through the vibration of the molecules of the medium is
Trả lời
(B)
conduction
20
A wave that travels through stretched strings is known as
Trả lời
(C)
mechanical wave
21
A transverse wave and a longitudinal wave travelling in the same direction in a medium differ essentially in their
Trả lời
(C)
direction of vibration of the particles of the medium
22
What is the velocity of sound at 100 oC if the velocity of sound at 0 oC is 340ms -1?
Trả lời
(C)
397m-1
23
If a sonometer has a fundamental frequency of 450HZ, what is the frequency of the fifth overtone?
Trả lời
(A)
2700Hz
24
A man 1.5m tall is standing 3m in front of a pinhole camera whose distance between the hole and the screen is 0.1m. What is the height of the image of the man on the screen?
Trả lời
(A)
0.05m
25
A ray of light passing through the centre of curvature of a concave mirror is reflected by the mirror at?
Trả lời
(A)
0o
26
Total internal reflection will not occur when light travels from
Trả lời
(B)
water into glass
27
If the linear magnification of the objective and eyepiece convex lenses of a compound microscope are 4 and 7 respectively. Calculate the angular magnification of the microscope
Trả lời
(D)
28
28
The angle of deviation of light of various colours passing through a triangular prism increases in the order
Trả lời
(A)
red → green → blue
29
Calculate the force acting on an electron of charge 1.5 x 10-19C placed in an electric field of intensity 105Vm-1
Trả lời
(D)
1.5x10-14N
30
Capacitors are used in the induction coil to
Trả lời
(C)
prevent electric sparks
31
A cell of emf 1.5V is connected in series with a 1Ω resistor and a current of 0.3A flows through the resistor. Find the internal resistance of the cell
Trả lời
(A)
4.0Ω
32
Which of the following obeys ohms laws?
Trả lời
(B)
metals
33
A house has ten 40W and five 100W bulbs. How much will it cost the owner of the house to keep them lit for 10 hours if the cost of a unit is 5N?
Trả lời
(C)
N45
34
An electric device is rated 2000W, 250V. Calculate the maximum current it can take
Trả lời
(B)
8A
35
When a charge moves through an electric circuit in the direction of an electric force, it
Trả lời
(C)
loses potential energy and gains kinetic energy
36
To convert a galvanometer to a voltmeter, a
Trả lời
(A)
high resistance is connected to it in series
37
Induced emfs are best explained using
Trả lời
(B)
Faraday's law
38
If a current of 2.5A flows through an electrolyte for 3 hours and 1.8g of a substance is deposited, what is the mass of the substance that will be deposited if a current of 4A flows through it for 4.8 hours?
Trả lời
(C)
4.6g
39
Calculate the energy of the third level of an atom if the ground state energy is - 24.8eV
Trả lời
(C)
-2.75eV
40
In photo-emission, the number of photo-electrons ejected per second depends on the?
