General Science Guide for Competitive Exams - CSAT/NDA/CDS/Railways/SSC/UPSC/State PSC/Defence

240 Pages·2017·12.38 MB·English

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INDEX
PHYSICS A-1-60
1. Measurements & Motion A-1-8
2. Laws of Motion, Force, Work, Energy & Power A-9-18
3. Force of Gravity, Solids & Fluids A-19-27
4. Sound, Oscillations, Heat & Termodynamics A-28-38
5. Electricity, Magnetism & Light A-39-50
6. Modern physics & Sources of energy A-51-60
CHEMISTRY B-1-60
1. Chemistry, Matter & its Composition B-1-14
2. Atoms, Molecules & Nuclear Chemistry B-15-22
3. Elements Classifcation & Chemical Bonding B-23-29
4. Acids, Bases, Salts & Metals B-30-38
5. Non - Metals B-40-43
6. Organic Chemistry B-44-48
7. Environmental Chemistry B-49-60
BIOLOGY C-1-68
1. Biological Classifcation/ Cell & its Division C-1-13
2. Genetics & Biotechnology C-14-20
3. Evolution and Ecological Biodiversity C-21-29
4. Tissue, Physiology of Plants and Animals C-30-46
5. Reproduction C-47-53
6. Nutrition, Health and Diseases C-54-63
7. Food Production C-64-68
SCIENCE & TECHNOLOGY D-1-48
1. Computer and Technology D-1-10
2. Communication D-11-17
3. Defence D-18-26
4. Space Technology D-27-33
5. Energy D-34-43
6. Nuclear Science D-44-48
physics
chapter
MeasureMents & Motion
1
MeasureMents S. Fundamental Fundamental Symbol
No. Physical quantity Unit
The process of comparing an unknown physical quantity with
1. Length metre m
respect to a known quantity is known as measurement. When we
say that the length of our bedroom is 10 feet it implies that the 2. Mass kilogram kg
bedroom is 10 times the known quantity ‘foot’ (feet is the plural 3. Time second s
of foot). So, measurement of any physical quantity consists of 4. Electric current ampere A
two parts – (i) a numerical value and (ii) the known quantity. 5. Temperature kelvin K
The known quantity is called the unit of that physical quantity.
Measurement is an integral part of physics. 6. Luminous intensity candela cd
Physics is the foundation on which engineering, technology and 7. Amount of mole mol
other sciences are based. substance
Derived units: Any unit which can be obtained by the
Physical quantities
combination of one or more fundamental units are called derived
Quantities which can be measured are called physical quantities. unit.
Velocity, acceleration, force, area, volume, pressure, etc. are some
examples of physical quantities. Examples: Area, speed, density, volume, momentum,
acceleration, force etc.
Kinds of Physical quantities Derived units of some physical quantities are as follows:
There are two kinds of physical quantities S. Derived Physical Derived Unit
Fundamental physical quantities: Fundamental physical No. quantity
quantities are those which do not depend on other quantities and
1. Area m2
a
lelnsog tihn,d meapsesn,d teimnte ,o tfh eramcho doythnaerm. iTch teym paerera steuvre,n e ilnec ntruicm cbuerrr evnizt;, 2. Volume m3
luminous intensity and amount of substance. 3. Density kg/ m3
Derived physical quantities: Derived physical quantities are 4. Speed m/s
those which are derived from fundamental physical quantities. 5. Acceleration m/s2
For example, velocity is derived from the fundamental quantities 6. Momentum kg m/ s
length and time, hence it is a derived physical quantity.
7. Force kg m/s2 or newton
units 8. Work kg m2/s2 or joule
To measure a physical quantity it is compared with a standard 9. Power kg m2/s3 or watt
quantity. This standard quantity is called the unit of that quantity. 10. Charge ampere-sec or coulomb
For example, to measure the length of a desk, it is compared with 11. Potential joule/coulomb or volt
the standard quantity known as ‘metre’. Thus, ‘metre’ is said to
be the unit of length. 12. Resistance volt/ampere or ohm
types of units systems of units
Depending upon the units of fundamental physical quantities,
There are two types of units : there are four main systems of units, namely
Fundamental units: Fundamental units are those units which • CGS (Centimeter, Gramme or Gram, Second)
cannot be derived from any other unit, and they cannot be • FPS (Foot, Pound, Second)
resolved into any basic or fundamental unit. Also, the units of • MKS (Meter, Kilogram, Second)
fundamental physical quantities are called fundamental units. • SI (Systeme Internationale d′ Unites)
The following table shows the seven fundamental units of S.I. The first three of these systems recognize only three
fundamental quantities i.e. length (L), mass (M) and
System.
a- 2 Physics
time (T) while the last one recognizes seven fundamental errors in MeasureMents
quantities. i.e. length (L), mass (M), time (T), electric
Generally measured value of a quantity is different from the true
current (I or A), thermodynamic temperature (K or q),
value of the physical quantity. The difference between the true
amount of substance (mol) and luminous intensity (I ).
v value and measured value is called error. Error = true value –
An international organization, the Conference Generale
measured value
des Poids et Mesures, or CGPM is internationally
Before we discuss about errors let us understand two important
recognized as the authority on the defnition of units. In
terms :
english, this body is known as “General Conference on
Accuracy : It is the measure of how close the measured value is to
Weights and Measure”. The Systeme International de
the true value of the physical quantity.
Unites, or SI system of units, was set up in 1960 by the
CGPM. Precision : It tells us about the limit or resolution upto which the
quantity is measured.
Characteristics of a Standard Unit
A standard unit must have following features to be accepted
Signifcant Figures
world wide. It should
• have a convenient size. Signifcant digits or fgures give information about the
• be very well defned. accuracy of a measurement. It tells us about the number of
• be independent of time and place. digits in which we have confdence. Suppose a particular
measurement is reported to be 9.28 cm, then the two digits 9
supplementary units of si system
and 2 are reliable and certain while the digit 8 is uncertain.
The following table shows the two supplementary units of SI. The reliable and frst uncertain digits are known as signifcant
System. digits or fgures.
There are certain rules for counting signifcant digits or fgure:
S.No. Physical Supplementary Symbol Rule-1. All the non-zero digits are signifcant—For example
quantity Unit 2134 has four signifcant fgures and 27184 has fve signifcant
fgures.
1. Plane angle radian rad
Rule-2. All the zeros between two non-zero digits are
2. Solid angle steradian sr
signifcant, no matter where the decimal point is, if at all. For
1. radian (rad): The radian is the plane angle between two radii example 25089 has fve signifcant fgures, 12.0021 has six
of a circle that cut off on the circumference an arc equal in signifcant fgures.
length to the radius. Rule-3. In a number which is less than one all zeros to the
2. steradian (sr): The steradian is the solid angle that, having right of decimal point but to the left of a non-zero digit are not
its vertex at the center of a sphere, cuts off an area of the signifcant.
surface of the sphere equal to that of a square with sides of Rule-4. All the zeros on the right of last non-zero digits are
length equal to the radius of the sphere. signifcant in a number with a decimal point. For example in
3.500 there are four signifcant digits and in 0.079000 there are
Practical units of length
fve signifcant fgures.
Astronomical unit, AU: The average distance between the sun
Rule-5. All the zeros on the right on a non-zero digit are not
11
and the earth about 1.49 × 10 m is called 1 AU. signifcant in a number without decimal point. For example
Parsec: The parsec is defned to be the distance at which a star 15800 has only three signifcant fgures, 18930000 has only
would have a parallax angle equal to one second of arc. four signifcant fgures.
1 Parsec = 3.08568025 × 1016 m. Rule-6. All the zeros on the right on a non-zero digit are taken
Light year : The light year is the distance travelled by light in one to be signifcant when these come from a measurement. For
year. All electromagnetic waves travel at a speed of 299,792,458 example some distance is measured to be 7890 m then this
-1 number would have four signifcant fgures.
ms and an average year being 365.25 days.
8 –1
One light year is 299,792,458 × 10 ms × (365.25 × 24 × 60 × 60) Rule-7. A change of system of units does not change the
15 12
s = 9.46073 × 10 m. or 9.46073 × 10 km. number of signifcant digits in a measurement. Also when
b
Angstrom: An angstrom is a unit of length used to measure small a number is written in scientifc notation (a × 10 ) then the
lengths such as the wavelengths of light, atoms and molecules. powers of 10 are irrelevant to the determination of signifcant
One angstrom ,1 Å =10–10m. fgures.
–15
Fermi: A unit of length used to measure nuclear distance = 10
least count (l.c.)
–15
meter, 1 fermi = 10 m.
The smallest division on the scale of the measuring instrument. It
is an uncertainty associated with the resolution of the measuring
Prefixes for si units
instrument.
In Physics we have to deal from very small (micro) to very large DiMensions of a Physical quantity
(macro) magnitudes. To express such large and small magnitudes
All physical quantities can be expressed in terms of the
simultaneously we use following prefxes:
fundamental quantities. Consider the physical quantity force.
When a prefix is placed before the symbol of unit, the
velocity
combined prefx and symbol should be considered as one new Force = mass × acceleration = mass ×
time
symbol which can be raised to a positive or negative power length / time
–2
3 3 3 = mass × = mass × length × time
without any bracket, e.g., km means (10 m) but never
time
3 3 –2
10 m . ∴ Unit of force = unit of mass × unit of length × (unit of time)
Measurements & Motion a- 3
Thus we can express the unit of force as products of different
Handy Facts
powers of the fundamental units of mass, length and time.
i.e., Force = [MLT–2] The actual distance travelled by an object in a given time interval
Thus the dimensions of a physical quantity are the powers to can be equal to or greater than the magnitude of displacement. It
which the fundamental quantities mass, length and time must be can never be less than the magnitude of displacement.
raised to represent it. The displacement of an object in a given time interval can
Science in Action be positive, zero or negative. However, distance covered
by the object in a given time interval is always positive.
A spring balance on the moon will give different reading
from that on Earth but a beam balance will give the same
reading as spring balance requires gravity to measure. Mass uniforM anD non-uniforM Motion
remains same throughout but weight changes with gravity.
uniform Motion
Mass will only change if there is any change in the volume
of matter in the body. It is a motion in which a body moves in a straight line (rectilinear)
and covers equal distances in equal intervals of time.
The path length of a body in a uniform rectilinear motion is
Motion equal to the magnitude of the displacement. Consequently, the
path length(s) in the motion is equal to the magnitude of the
velocity (v) multiplied by the time (t) i.e., s = vt.
rest anD Motion
Rest : An object is said to be at rest if it does not change its position Handy Facts
with respect to its surroundings with the passage of time. No force is required to keep an object in uniform motion.
Motion : A body is said to be in motion if its position changes When an object has uniform motion along a straight line
continuously with respect to the surroundings (or with respect to
in a given direction, the magnitude of displacement is
an observer) with the passage of time.
equal to actual distance covered.
Rest and motion are relative terms.
types of Motion on the basis of Dimensions non-uniform Motion
One-Dimensional Motion: It is the motion in which If a body covers unequal distances in equal intervals of time, it
the position of the object changes only in one direction. In this case is said to be moving with a non-uniform motion. It is a motion in
the object moves along a line. For example – motion of a train which the velocity varies with time. The change in the velocity of
along a straight line, freely falling object under gravity, etc. a body in non-uniform motion is characterized by acceleration.
Two-Dimensional Motion: It is the motion in which the position Uniformly variable motion is a motion with a constant
of the object changes in two directions. In this case the object acceleration. Uniformly variable motion can be curvilinear like
moves on a plane. For example – projectile motion. circular motion. If a uniformly variable motion is rectilinear, i.e.,
Three-Dimensional Motion: It is the motion in which the the velocity v changes only in magnitude, it is convenient to take
position of the object changes in three directions. In this case the the straight line in which a material point moves as one of the
object moves in a space. For example – a bird fying in the sky. coordinate axes (say, the x-axis).
the rate of Motion
Distance anD DisPlaceMent average speed
Motion is related to change of position. The length travelled in
It is defned as the total distance travelled divided by the time
changing position may be expressed in terms of distance, i.e.,
interval to travel that distance.
the actual path length between two points.
Distance is a scalar quantity, which has only a magnitude with d
no direction. Average speed Vav = ,d is distance travelled, and t is time
t
The direct straight line pointing from the initial point to the fnal
interval (change in time).
point is called displacement (change in position). Displacement
only measures the change in position, not the details involved in The average speed of Cheetah is 70 m/s for 30 seconds
the change in position.
Displacement is a vector quantity, which has both magnitude instantaneous speed
and direction. It is the speed at a particular time instant (t is infnitesimal small
The displacement can be zero, even if the distance is not zero. or close to zero).
For example when a body is thrown vertically upwards from a uniform and non-uniform speed
point on the ground, after sometime it returns back to the same A body is said to be moving with uniform speed if it covers equal
point, then the displacement of the body is zero but the distance distances in equal time intervals and with non-uniform or variable
travelled by the body is not zero, it is 2h if h is the maximum speed if covers unequal distances in the same time intervals.
height attained by the body.
Similarly, if a body is moving in a circular or closed path sPeeD with Direction (velocity)
and reaches its original position after one revolution, then the
average velocity
displacement in one revolution is zero, but the distance travelled
is equal to the circumference of the circular path = 2πr if r is the It is defned as the ratio of change in position or displacement
radius of the circular path. to the time taken.
a- 4 Physics
x
2 − x1 ∆x Handy Facts
v = v = =
av
t − t ∆t The x-t graph of an object having uniform motion is a straight
2 1

line inclined to the time-axis. The slope of straight line x-t
H x e ar ena dr e x t ht e a n p d o s t i t i o n s o f t h e p a r t i c l e a t t i m e
1 2 1 2 graph gives velocity of the uniform motion of the object.
r e s Dp x e – c = = t x i c xv Dh e= t ta l n y g . e A i l ns o p , o s i t i o n a n d
2 1 2
– 1 – 1 – 1
–
1 = t c h a, n cgo . mer s velikocityn-mtime grat phhs i m e . I t s u n i t i s m s
This is the velocity-time graph of a cyclist travelling from A to B
in s t vea l n o t ca i n t e y o u s
at a constant acceleration, i.e. with steadily increasing velocity.
V e l o c i t y o f a b o d y a t a p a r t i c u l a r i n s t a n t o r m o m e n t o f t i m e i s
∆s
c a l l e d i n s t a n t a n e o u s v e l o c i t y .
The gradient of this graph is just and this is just the expression
∆t
for acceleration. Because the slope is the same at all points on this
r a t e o f c h a n g e o f v e l o c i t y
graph, the acceleration of the cyclist is constant.
[ a c c e l e r a t i o n ]
B
10 B
P o s i t i v e a c c e l e r a t i o n : I f t h e v e l o c i t y o f a n o b j e c t i n c r e a s e s i n
t h e s a m e d i r e c t i o n , t h e o b j e c t h a s a p o s i t i v e a c c e l e r a t i o n .
Dv
N e g a t i v e a c c e l e r a t i o n ( R e t a r d a t i o n ) : I f t h e v e l o c i t y
o f a b o d y d e c r e Dt a s e s i n t h e s a m e d i r e c t i o n , t h e b o d y
h a s a n e g a t i v e a c c e l e r a t i o n o r i t i s s a i d t o b e r e t a r d i n g
e . g , a t r a i n s l o w s d o w n .
A Time A Time (s) 5
The slope of a velocity-time graph gives the acceleration.
Observe the following velocity-time graphs.
gr Pha irePrc ea sl eM o n t t i a o t n i o n o f
i n a s t r a i g h t l i n e
y
D i s ti p gmrl aea pc he Csm e n t -
A g r a p h s h o w i n g t h e d i s p l a c e m e n t
o f t h e c y c l i s t f r o m A t o C :
T h i s g r a p Ds h s h o w s u s h o w , i n
t s e c o n d s t i m e , t h e c y c l i s t h a s m o v e d
Dt Time Time
f r o m A t o C .
(a) (b)
W e k n o w t h e g r a d i e n t ( s l o p e ) o f
Graph (a) shows the object is moving at a constant velocity
a g ri d as e ap t f shc h n h e e a d n g e
over a period of time. The gradient is zero, so the
i y dnivided by the change in x,
object is not accelerating.
∆y x
i.e., . A T i m Geraph (b) shsows )an object which is decelerating. You can
∆x 
∆s see that the velocity is decreasing with time. The
In this graph the gradient of the graph is just and this is just
gradient, however, stays constant so the acceleration
∆t
the expression for velocity.
is constant. Here the gradient is negative, so the object
is accelerating in the opposite direction to its motion,
The slope of a displacement-time graph gives the velocity.
hence it is decelerating.
The slope is the same all the way from A to C, so the cyclist’s
velocity is constant over the entire displacement he travels.
acceleration-time graphs
Observe the following displacement-time graphs.
Observe the following acceleration-time graphs.
Time
Time Time
(a)
(b) (c)
Graph (a) shows the object is stationary over a period of time.
The gradient is zero, so the object has zero velocity. Time Time
(a) (b)
Graph (b) shows the object is moving at a constant velocity. You
can see that the displacement is increasing as time goes Graph (a) shows an object which is either stationary or travelling
on. The gradient, however, stays constant so the velocity at a constant velocity. Either way, the acceleration is
is constant. Here the gradient is positive, so the object is zero over time.
Graph (b) shows an object moving at a constant acceleration.
moving in the direction we have defned as positive.
In this case the acceleration is positive - remember
Graph (c) shows the object is moving at a constant acceleration.
that it can also be negative.
You can see that both the displacement and the
velocity (gradient of the graph) increases with time. equations of Motion
The gradient is increasing with time, thus the velocity Kinematic equations can be used to describe the motion with
is increasing with time and the object is accelerating. constant acceleration.
Displacement
Displacement
Displacement D i s p l a c e m e n t ( m )
Acceleration Velocity
Velocity (m/s)
Velocity
Acceleration
Velocity (m/s)
Measurements & Motion a- 5
first equation (equation for velocity-time relation) : Case-II: Body thrown upward:
If a body is thrown vertically up with an initial velocity (u).
Final velocity
Hence a = – g. Kinematic equations will be:
= initial velocity + acceleration × time interval
1 2
or v = u + at (i) v = u – gt (ii) h = ut − gt
2
second equation (equation for position-time relation) :
 1
2 2
1 (iii) v – u = – 2gh (iv) h
n = u – g  n − 
Displacement = initial velocity × time interval +  2
2
2 M a x i m u m h e i g h t r e a c h e d b y t h e b o d y
× acceleration × time interval
2 2
F r o v = m + u e 2 q g u h a t i o n
1 2
2
or s = ut + at u
2 H = [v = 0 ]
2g
third equation (equation for position-velocity
2 2 T h e r e f o r e , t h e m a x i m u m h e i g h t r e a c h e d b y t h e b o d y i s d i r e c t l y
relation) : v = u + 2as
2 2 p r o p o r t i. o n a l t o t h e s q u a r e o f t h e i n i t i a l v e l o c i t y
Final velocity = initial velocity +
T i m ) eT : h o e f t ai sm c e e nt ta k ( e t n b y a b o d y t h r o w n u p t o
2 × acceleration × displacement a
2 2 r e a c h m a x i m u m h e i g h t ‘ h ’ i s c a l l e d i t s t i m e o f a s c e n t .
or v = u + 2as u
t =
a
g

relative Motion
H e n c e i s t i d m i e r e o c f t l a y s c p e r n o t p o t r t i o n a l t o t h e i n i t i a l
a
The motion of an object B w.r.t. object A which is moving or v e u l . o c i t y
stationary is called as relative motion. T i m ) eT : h o e f t di em s e c et na tk e ( n t b y a f r e e l y f a l l i n g b o d y t o
d
Relative velocity of an object B w.r.t. object A when both are in r e a c h t h e g r o u n d i s c a l l e d t h e t i m e o f d e s c e n t .
motion is the rate of change of position of object B w.r.t. object A.
Relative velocity of object B w.r.t. object A, VBA = VB - VA 2h
t =
d
g
Mo t u Di en gor rn a v i t y
a = + g
2
v v h
It is a common experience that when a body is dropped form a
a n d h = , t =
d
certain height it experiences acceleration due to gravity and its 2g g
motion is in a straight path. Similarly, when a body is thrown
u v = u
vertically up, it goes to a certain height and then starts falling again,
B u t , w e k n o w t h a t u = v i . e . , p r o j e c t e d v e l o c i t y o f a b o d y i s e q u a l
experiencing acceleration due to gravity throughout the motion.
2 t o t h e v e l o c i t y o f t h e b o d y o n r e a c h i n g t h e g r o u n d .
The value of acceleration due to gravity (g) is taken as 9.8 m/s ,
2 2 u
980 cm/s or 32 ft/s . ∴ t = = tt ) i m e o f a s c e n t (
d a
Let us consider the three cases discussed below. g
T i m e o f a s c e n t = t i m e o f d e s c e n t
Case-I: Body thrown downward : u
g
In this case, initial motion of the C a s e - I I I : B o d y p r o j e c t e d v e r t i c a l l y u p f r o m t h e t o p o f a
body is downward so according t o w e r :
to the sign convention, downward h
I f a b o d y i s p r o j e c t e d v e r t i c a l l y u p f r o m t h e t o p o f a t o w e r o f
direction will be taken as positive and
h e i ug ’h .t T‘ h ’e n w i t h v e l o c i t y ‘
upward direction as negative. So, the
kinematic equations will be : 1 2
D i s tp s = l ui a− ts c e g mt e n t a f t e r t i m e
(i) v = u + gt v 2
1 V e l t o i c s i t v y = a f u t e – r g t t i . m e
2
(ii) h = ut + gt
2
2 V e l o c u +i2 t g y h o n r e a c h i n g t h e g r o u n d i s
2 2
(iii) v = u + 2gh 2
Maximum height above the ground is {h + (u /2g)}
1
nth
(iv) h = h + g (2n – 1)
2 Projectile Motion
In a special case when the body is dropped/let falls i.e., initial Projectile is the name given to a body thrown with some initial
velocity (u) = 0, then equation becomes velocity in any arbitrary direction and then allowed to move
1 1 under the infuence of a constant acceleration. The motion of a
2 2 nth
v = gt ; h = gt ; v = 2gh ; h = g (2n – 1)
projectile is called projectile motion.
2 2
Example : A football kicked by the player, a stone thrown from
Science in Action the top of building, a bomb released from a plane.
According to Galileo, when two bodies of different masses are The path followed by a projectile is called its trajectory, mostly,
the trajectory of a projectile is parabolic.
dropped from the same height both will touch the foor at the
same time in the absence of air resistance. If a ping pong and Maximum height (H): When a projectile moves, it covers a
maximum distance in vertical direction. This maximum distance is
basket ball are dropped the foor from same height, they will
called the maximum height attained by the projectile.
hit at the same time in the absence of air resistance.
a- 6 Physics
u2 sin2 α Science in Action
Maximum height H =
2g • An aeroplane flying at a constant speed, if it releases a bomb,
Horizontal range (R): The horizontal distance between the the bomb moves away from the aeroplane and it will be always
point of projection and the point of landing of a projectile. vertical below the aeroplane as the horizontal component of the
velocity of the bomb will be same as that of the velocity of the
2
Maximum range R = u sin 2α aeroplane. And thus the horizontal displacement remain same at
g
any instant of time.
Time of fight (T): The time taken by the projectile to reach the • If two bullets are fred horizontally, simultaneously and with
point of landing from the point of projection. different velocities from the same place, both the bullets will
hit the ground simultaneously as the initial velocity in the
Time of fight T = 2u s
gin α vertically downward direction is zero and same height has
to be covered.
exercise
1. Which of the following systems of units is not based on 10. Assertion : Number of signifcant fgures in 0.005 is one
units of mass, length and time alone? and that in 0.500 is three.
(a) SI (b) MKS Reason : This is because zeros are not signifcant.
(b) CGS (d) FPS (a) If both Assertion and Reason are correct and Reason
2. Mass is the measure of is the correct explanation of Assertion.
(a) matter contained (b) weight (b) If both Assertion and Reason are correct, but Reason
(c) force (d) none of these is not the correct explanation of Assertion.
3. Among the following the derived quantity is (c) If Assertion is correct but Reason is incorrect.
(a) mass (b) length (d) If Assertion is incorrect but Reason is correct.
(c) density (d) time 11. Match List I (Physical quantity) with List II (Units) and
4. Which of the following is not a fundamental unit? select the correct answer using the codes given below the
(a) newton (b) kilogram lists.
(c) metre (d) second List I (Physical quantity) List II (Units)
5. In SI units the number of basic physical quantities are A. Power 1. kg ms–1
(a) 3 (b) 7 B. Energy 2. kg m2s–1
(c) 9 (d) 21 C. Momentum 3. Nm–2
6. Light year is [SSC CGL] D. Pressure 4. kW
(a) light emitted by the sun in one year 5. kWh
(b) time taken by light to travel from sun to earth
Codes
(c) the distance travelled by light in free space in one year
A B C D
(d) time taken by earth to go once around the sun
(a) 4 5 1 3
7. One micron equals to
(a) 10–3 m (b) 10–9 m (b) 4 5 1 2
(c) 10–6 m (d) 10–2 m (c) 5 4 1 2
(d) 5 4 2 3
8. Practical unit of heat is
12. What is the correct sequence in which the lengths of the
(a) Calorie (b) Horse power
following units increase?
(c) Joule (d) Watt
1. Angstrom 2. Micron 3. Nanometer
9. Match List I (Units) with List II (Physical quantity) and
Select the correct answer using the code given below:
select the correct answer using the codes given below the
[NDA]
lists. [CDS]
(a) 1, 2, 3 (b) 3, 1, 2
List I (Units) List II
(c) 1, 3, 2 (d) 2, 3, 1
(Physical quantity)
13. Which one of the following is not a dimension less quantity?
(A) Watt 1. Electric charge
(a) Strain (b) Relative density
(B) Tesla 2. Power
(c) Frequency (d) Angle
(C) Coulomb 3. Luminous intensity
(D) Candela 4 Magnetic feld 14. Match List 'I' (Physical quantity) with list II (Dimension)
Codes and select the correct answer by using the codes given below
A B C D the lists.
List I (Physical quantity) List II (Dimension)
(a) 1 4 1 3
A. Density 1. [MLT–2]
(b) 1 2 3 4
B. Force 2. [ML–3]
(c) 1 2 4 3
C. Energy 3. [MLT–1]
(d) 2 4 3 1
D. Momentum 4. [ML2T–2]