UNIFORM MOTION AND NON-UNIFORM MOTION

If a body travels equal distances in equal
intervals of time, then the body is said to be in Uniform motion.
Ex-  A car running at a constant speed of 10 metres per second, will cover equal distances of 10 metres, every second, so its motion will be uniform.
- The distance-time graph for uniform motion is a straight line. 

If a body travels unequal distances in equal intervals of time, then the body is said to be in non-uniform motion.
Ex- if we drop a ball from the roof of a tall building, we will find that it covers unequal
distances in equal intervals of time.
- The distance-time graph for a
body having non-uniform motion
is a curved line.

MEASURING THE RATE OF MOTION

- The speed of a body gives us an idea of how slow or fast that body is moving.
- Speed of a body is the distance travelled by it per unit time.
- The speed of a body can be calculated by dividing the ‘Distance travelled’ by the
‘Time taken’ to travel this distance.

- The SI unit of speed is metres per second.

- The other units of speed includes centemeter per second and kilometre per hour. 

- The average speed of a body is total distance traveled devided by total time taken. 

SPEED WITH DIRECTION (Velocity)

- The quantity that specifies both direction of motion along with speed is called velocity.
- Velocity of a body is the distance travelled by it per unit time in a given direction.

Where v = velocity of the body
          s = distance travelled (in the given direction)
and t = time taken (to travel that distance) 

- The SI unit of velocity is the same as that of speed, namely, metres per second (m/s).
- The difference between speed and velocity is that speed has only magnitude (or size), it has no specific direction, but velocity has magnitude as well as direction.
- The magnitude of speed and velocity of a moving body is equal only if the body moves in a single straight line.
- In case the velocity of the object is
changing at a uniform rate, then average
velocity is given by the arithmetic mean of
initial velocity and final velocity for a given
period of time.
- The average speed of a
moving body can never be zero, but the average velocity of a moving body can be zero.

RATE OF CHANGE OF VELOCITY (Acceleration)

- Acceleration of a body is defined as the rate of change of its velocity with time.

Change in velocity = Final velocity – Initial velocity
So,
- SI unit of acceleration is “metres per second square” which is written as m/s2.
- Acceleration is a vector quantity.
- When a body is moving with uniform velocity, its acceleration will be zero.

GRAPHICAL REPRESENTATION OF MOTION

1. DISTANCE–TIME GRAPHS

- When a body moves with uniform speed, it will travel equal distances in equal intervals of time.
- The distance-time graph of a body moving at uniform speed is always a straight line.

- The slope of a distance-time graph indicates speed.
- If, however, the speed of a body is non-uniform, then the graph between distance travelled and time is a curved line (called a parabola).

2. SPEED-TIME GRAPHS (OR VELOCITY-TIME GRAPHS)

We can have three types of speed-time graphs for a moving body. 

(i) Speed-Time Graph when the Speed Remains Constant

- Speed-time graph for a body moving with constant speed (or uniform speed) is
a straight line parallel to the time axis.

We can, however, find the distance travelled by the body in a given time from such a speed-time graph.
We know that
So, Distance travelled = Speed × Time taken ... (1)
Now, to find out the distance travelled by the body at point C , we draw a perpendicular CB at point C which meets the straight-line graph at point B.
Now, Speed at C = CB
But CB = OA
Thus, Speed at C = OA ... (2)
And, Time at C = OC ... (3)
Now, putting these values of speed and time in relation (1), we get :
Distance travelled = OA × OC
or Distance travelled = Area of rectangle OABC
Thus, in a speed-time graph, the area enclosed by the speed-time curve and the time axis gives us the distance travelled by the body.

(ii) Speed-Time Graph when Speed Changes at a Uniform Rate (Uniform Acceleration)

- The speed-time graph for a uniformly changing speed (or uniform acceleration) will be a straight line.

- The slope of a speed-time graph of a moving body gives its acceleration.
- a speed-time graph of a body, a straight line sloping downwards indicates uniform retardation. 

(iii) Speed-Time Graph when Speed Changes at a Non-Uniform Rate (Non-Uniform Acceleration)

- When the speed of a body changes in an irregular manner, then the speed-time graph of the body is a curved line.
- The distance travelled by the body is given by the area between the speed-time curve and the time axis.

EQUATIONS OF MOTION BY GRAPHICAL METHOD 

The three equations of motion : v = u + at ;  s = ut + 1/2 at2 and v2 = u2 + 2as can be derived with the help of graphs as described below.

1. EQUATION FOR VELOCITY-TIME
RELATION

The body has an initial velocity 'u' at point A and then its velocity changes at a uniform rate from A to B in time 't'.
There is a uniform acceleration a from A to B, and after time 't' its final velocity becomes 'v'.
which is equal to BC in the graph .
The time 't' is represented by OC.
Now,
Initial velocity of the body, u = OA ... (1)
And, Final velocity of the body, v = BC ... (2)
But from the graph BC = BD + DC
Therefore, v = BD + DC ... (3)
Again DC = OA
So, v = BD + OA
Now, From equation (1), OA = u
So, v = BD + u ... (4)
We should find out the value of BD now. We know that the slope of a velocity-time graph is equal to acceleration, 'a'.
Thus, Acceleration, a = slope of line AB
or

But AD = OC = t, so putting t in place of AD in the above relation, we get :

or BD = at
Now, putting this value of BD in equation (4) we get :
v = at + u
This equation can be rearranged to give :
v = u + at

This is the first equation of motion.

2. EQUATION FOR POSITION-TIME
RELATION

The body travels a distance s in time t.
The distance travelled by the body is given
by the area of the space between the velocity-time graph AB and the time axis OC, which is equal to the area of the figure OABC.
Thus : Distance travelled = Area of figure OABC
= Area of rectangle OADC + Area of triangle ABD
We will now find out the area of the rectangle OADC and the area of the triangle ABD.
(i) Area of rectangle OADC = OA × OC
= u × t
= ut ... (5)
(ii) Area of triangle ABD = 1/2 × Area of rectangle AEBD
= 1/2 × AD × BD
= 1/2 × t × at (because AD = t and BD = at)
= 1/2 at2 ... (6)
So, Distance travelled, s = Area of rectangle OADC + Area of triangle ABD
or s = ut + 1/2 at2

This is the second equation of motion.

3. EQUATION FOR POSITION–VELOCITY RELATION

We have just seen that the distance travelled s by a body in time t is given by the area of the figure OABC which is a trapezium .
Distance travelled, s = Area of trapezium OABC

Now, OA + CB = u + v and OC = t. Putting these values in the above relation, we get :
Eliminate 't' from the above equation. This can be done by obtaining the value of t from the first equation of motion.

Thus, v = u + at (First equation of motion)
And, at = v – u
So,

Now, putting this value of t in equation (7) above, we get :
or 2as = v2 – u2
or v2 = u2 + 2as

This is the third equation of motion.

UNIFORM CIRCULAR MOTION

- When a body (or an object) moves in a circle, it is called circular motion.

- When a body (or object) moves along a circular path, then its direction of motion (or direction of speed) keeps changing continuously.
- If a body moving in circular path with constant speed, it's velocity is not constant because direction of the body changing continuously.
- When a body moves in a circular path with uniform speed (constant speed), its motion is called uniform circular motion.
- The motion in a circle with constant speed is
an example of accelerated motion.
- The force which is needed to make an object travel in a circular path is called centripetal force.
Example:-
1. The earth moves around the sun in uniform circular motion.
2. The tip of a seconds’ hand of a watch exhibits uniform circular motion on the circular dial of the watch.

SPEED OF A BODY IN CIRCULAR MOTION

When a body takes one round of a circular path, then it travels a distance equal to its ‘circumference’ which is given by 2¶r. 

Where 'r' is the radius of the circular path. T

speed of a body moving along a circular path is given by the formula :
where      v = speed 

This is the formula for speed of a Body in uniform circular motion.

- Electric charge is the physical property of matter that causes it to experience a force when placed in an electromagnetic field.  

- There are two types of electric charge: positive and negative.

- Opposite charges (or Unlike charges) attract each other. 

- Similar charges (or Like charges) repel each other. 

- The SI unit of electric charge is coulomb which is denoted by the letter C. 

- The electric potential  at a point in an electric field is defined as the work done in moving a unit positive charge from infinity to that point. 

- It is denoted by the symbol V and its unit is volt. 

- A potential of 1 volt at a point means that 1 joule of work is done in moving 1 unit positive charge from infinity to that point. 

- The potential difference between two points in an electric circuit is defined as the amount of work done in moving a unit charge from one point to the other point. 

- The potential difference between two points is said to be 1 volt if 1 joule of work is done in moving 1 coulomb of electric charge from one point to the other.

- The SI unit of potential difference is volt which is denoted by the letter V. 

- The potential difference is measured by

means of an instrument called voltmeter.

difference. 

- When two charged bodies at different electric potentials are connected by a metal wire, then electric charges will flow from the body at higher potential to the one at lower potential (till they both acquire the same potential). This flow of charges in the metal wire constitutes an electric current.

- Electric current is expressed by the amount of charge flowing through a particular area in unit time. 

- If a charge of Q coulombs flows through a conductor in time t seconds, then the magnitude I of the electric current flowing through it is given by : 

- The SI unit of electric current is ampere which is denoted by the letter A. 

- When 1 coulomb of charge flows through any cross-section of a conductor in 1 second, the electric current flowing through it is said to be 1 ampere.

- Current is measured by an instrument called

ammeter.

-  An ammeter should have very

low resistance.

1 mA = 10–3 A

1 µA = 10–6 A

- A continuous conducting path consisting of wires and other resistances (like electric bulb, etc.) and a switch, between the two terminals of a cell or a battery along which an electric

current flows, is called a circuit.

- Conventional symbols used to represent some of the most commonly used electrical components are 

- In this circuit, a resistor R has been connected to the two terminals of a cell through a switch. An ammeter A has been put in series with the resistor R. This is to measure current in the

circuit. A voltmeter V has been connected across the ends of the resistor R, that is, voltmeter is connected in parallel with the resistor. This voltmeter is to measure potential difference (or voltage) across the ends of

the resistor R. 

- Ohm’s law gives a relationship between current and potential difference. 

- According to Ohm’s law : At constant temperature, the current flowing through a conductor is directly proportional to the potential difference across its ends. 

- If I is the current flowing through a conductor and V is the potential difference (or voltage) across its ends, then according to Ohm’s law : 

Where R is resistance of conductor (Constant)

The above equation can also be written as :

This is the mathematical expression of Ohm’s law.

The ratio of potential difference applied between the ends of a conductor and the

current flowing through it is a constant quantity called resistance.

Current, I = V/R

- It is obvious from this relation that :

(i) the current is directly proportional to potential difference. 

(ii) the current is inversely proportional to resistance.

- electric current in a given conductor depends on two factors :

(i) potential difference across the ends of the conductor, 

(ii) resistance of the conductor.

The property of a conductor due to which it opposes the flow of current through it is called resistance.

-  1 ohm is the resistance of a conductor such that when

a potential difference of 1 volt is applied to its ends, a current of 1 ampere flows through it. 

- The resistance of a conductor depends on

 (i) Length 

(ii) Thickness 

(iii) Nature of material 

(iv) Temperature, of

the conductor. 

- The SI unit of resistance is ohm which is denoted by the symbol omega.

- In the electrical circuits of radio,

television and other similar things, it is usually necessary to

combine two or more resistances to get the required current in the

circuit. 

- The

resistances can be combined in two ways : (i) in series, and (ii) in

parallel.

- If we want to increase the total resistance, then the individual resistances are connected in series.

- According to the law of combination of resistances in series : The combined resistance of any number of resistances connected in

series is equal to the sum of the individual resistances. 

Ex- If a number of resistances R1, R2, R3

...... etc., are connected in series, then their combined resistance R is given by : R = R1 + R2 + R3 +.........

- When a number of resistances connected in series are joined to the terminals of a battery, then each resistance has a different potential difference across its ends . But the total potential difference across the ends of all the resistances in series is equal to the voltage of the battery. 

- When a number of resistances are connected in series, then the same current flows through each resistance (which is equal to the current flowing in the whole circuit).

Resultant Resistance of  Resistances Connected in Series

 Three resistances R1, R2 and R3 connected in series.

A battery of V volts has been applied to the ends of this series combination of resistances.

  Now, suppose the potential difference

across the resistance R1 is V1, R2 is V2 and R3 is V3.

 The total potential difference across the three

resistances should be equal to the voltage of the battery applied. That

is,    V = V1 + V2 + V3        ... (1)

 The total potential difference due to battery

is V. 

 The total resistance of the combination be R.

 The current flowing through the whole circuit is I.

So, applying Ohm’s law to the whole circuit, we get : 

                      or             V = I × R

Since the same current I flows through all the resistances R1, R2 and R3 in series, so by applying Ohm’s

law to each resistance separately, we will get :

       V1 = I × R1 ... (3)

       V2 = I × R2 ... (4)

and V3 = I × R3 ... (5)

Putting these values of V, V1, V2 and V3 in equation (1), we get :

                I × R = I × R1 + I × R2 + I × R3

or             I × R = I × (R1 + R2 + R3)

Cancelling I from both sides, we get :

                R = R1 + R2 + R3

If three resistors R1, R2, and R3 are connected in series then their total resistance R is given by the formula :

                R = R1 + R2 + R3

If there are 'n' resistors R1, R2, R3,...... Rn connected in series, then their resultant resistance

R is given by the formula : 

        R = R1 + R2 + R3 + ........... + Rn

- If we want to decrease the resistance, then the individual resistances are connected

in parallel. 

- According to the law of combination of resistances in parallel : The reciprocal of the combined resistance of a number of resistances connected in parallel is equal to the sum of the reciprocals of all the individual resistances.

Ex- if a number of resistances, R1, R2, R3 ...... etc., are connected in parallel, then their combined resistance R is given by the formula : 

- When a number of resistances are connected in parallel then their combined resistance is

less than the smallest individual resistance. 

- When a number of resistances are connected in parallel, then the potential difference across each

resistance is the same which is equal to the voltage of the battery applied.

- When a number of resistances connected in parallel are joined to the two terminals of a battery, then different amounts of current flow through each resistance. But the current flowing through all the individual parallel resistances, taken together, is equal to the current flowing in the circuit as a whole. 

Resultant Resistance of  Resistances Connected in Parallel

 Three resistances R1, R2 and R3 are connected parallel.

  A battery of V volts has been applied across the ends of this combination. In this case the

potential difference across the ends of all the three resistances will be the same. And it will be equal to the voltage of the battery used. 

 Suppose the total current flowing through the circuit is I.

 The current passing through resistance R1 will be I1, R2 will be I2, R3 will be I3.

1. In series circuit, if one electrical appliance stops working due to some defect, then all other appliances also stop working.

2. In series circuit, all the electrical appliances have only one switch due to which they cannot be turned on or off separately. 

3. In series circuit, the appliances do not get the same voltage (220 V) as that of the power supply line. 

4. In the series connection of electrical appliances, the overall resistance of the circuit increases too much due to which the current from the power supply is low. 

1. In parallel circuits, if one electrical appliance stops working due to some defect, then all other appliances keep working normally.

2. In parallel circuits, each electrical appliance has its own switch due to which it can be turned on or turned off independently, without affecting other appliances.

3. In parallel circuits, each electrical appliance gets the same voltage (220 V) as that of the power supply line.

4. In the parallel connection of electrical appliances, the overall resistance of the household circuit is reduced due to which the current from the power supply is high. 

 When an electric current is passed through a high resistance wire, like nichrome wire, the resistance wire becomes very hot  and produces heat. This is called the heating effect of current.

  The heating effect of current is obtained by the transformation of electrical energy into heat energy. 

  Heat produced, H = I2 × R × t joules

This formula gives us the heat produced in joules when a current of I amperes flows in a wire of resistance R ohms for time t seconds. 

  This is known as Joule’s law of heating. 

 The heat produced in a wire is directly proportional to :

(i) square of current (I2)

(ii) resistance of wire (R)

(iii) time (t), for which current is passed.

- A given current will produce more heat in a high resistance wire than in a low resistance wire.

- A given current will produce more heat per unit time if the two resistances are connected in series than in parallel.

- All the appliances which run on electricity

do not convert all the electric energy into heat energy.

1. The heating effect of current is utilised in the working of electrical heating appliances such as

electric iron, electric kettle, electric toaster, electric oven, room heaters, water heaters (geysers), etc. 

2. The heating effect of electric current is utilised in electric bulbs (electric lamps) for producing light.

3. The heating effect of electric current is utilised in electric fuse for protecting

household wiring and electrical appliances.

- Electric power is the electrical work done per unit time.

- SI unit of electric power is watt.

- The power of 1 watt is a rate of working of 1 joule per second. 

Formula for Calculating Electric Power

Electric power = Potential difference × Current

Electric power = Voltage × Current

Climate :

Weather :

Monsoon: 

Climatic controls

Latitude:-

Altitude:- 

Pressure and wind system:- 

Distance from the sea:-

Ocean currents:-

Relief:-

FACTORS AFFECTING INDIA’S CLIMATE

Latitude:- 

Altitude:-

Pressure and Winds:-

Coriolis force:- 

Western Cyclonic Disturbances

Jet Stream

Jet Stream

THE INDIAN MONSOON

Atmospheric Conditions over the Indian Subcontinent in the Month of January (Ref: NCERT)

Atmospheric Conditions over the Indian Subcontinent in the Month of June (Ref: NCERT)

Inter Tropical Convergence Zone (ITCZ)

El Nino

The Onset Of The Monsoon And Withdrawal

The Season

1. The Cold Weather Season (Winter)

2. The Hot Weather Season (Summer)

3. Advancing Monsoon (The Rainy Season)

4. Retreating/Post Monsoons (The Transition Season)

DISTRIBUTION OF RAINFALL

NCERT solutions class 10 chapter 2  Acids, Bases and Salts

Here we have provided NCERT solutions for class 10 chapter 2  Acids, Bases and Salts according to lattest pattern released by CBSE.

Before going to NCERT solutions for class 10 chapter 2  Acids, Bases and Salts. Let's have a look at the Quick Revision notes of  Class 10 Chapter 2 Acids, Bases and Salts

In Text Questions

Page no - 18

1. You have been provided with three test tubes. One of them contains
distilled water and the other two contain an acidic solution and a basic
solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?

Answer:
Step-1   Add the litmus paper to all three test tube. The solution which turns the red litmus to blue will be basic soluttion.
Step-2 Now put the blue litmus paper obtained above in the remaining two test tubes. The solution which turn blue litmus paper to red is acidic solution.
Step-3 The solution which remains neutral to both litmus paper will be distilled water.

Page no - 22



Quick revision note of class 10 science
chapter 3 Acids, Bases and Salts