Category: Physics Notes PPT

As we all know according to the conservation of energy, the energy can neither be created nor be destroyed. In our day today’s life, we observe that all the electrical equipment used in our household utilizes the same electricity. The same electricity that is used for rotating fans is also used for heating our electric toaster, etc. 

We are always witnessing the heating effect of electric current in our everyday lives unknowingly. We observe that whenever an electric bulb is turned on it will be hot after sometimes, or when we charge our cellphones we end up feeling heat vibrations. Why does all this happen? This is what we say the heating effects of electric current.

The loss in electrical energy in any device appears as thermal energy. When electrical energy is converted into heat energy, it is known as the heating effect of electric current.

Explain the Heating Effect of Electric Current

Whenever electric current is passed through materials, it will discharge energy in the form of heat energy. This conversion of electrical energy into heat energy known as the heating effect of electric current. Though it is a loss of energy, this loss of energy is utilized for doing certain useful things, like we use iron boxes for pressing clothes, electric heaters for boiling water, etc. 

The heating effect of electric current is well explained with a mathematical description given by Joule’s law. Joule’s law says that the amount of heat generated is directly proportional to the current flowing through the wire and the resistance of the material.

The heating effect of electric current is exhibited by Joule’s law. Mathematically, Joule’s law is given by,

=> H = I2Rt

Where,

H – The amount of heat produced

I – The amount of electricity passing through the wire

t – Time taken for heat generation

Application of the Heating Effect of Current

1. The electric bulb is one of the basic applications of heating effects of electricity. The tungsten filament used will discharge its energy as heat and light.

2. The effect is well used in the electric iron boxes.

3. Electric heaters are the most widely used domestic equipment for boiling waters.

Solved Examples

Question: Copper and Nichrome wires are connected in series. In which case the possibility of heat production will be more?

Ans: According to joule’s law the amount of heat generated will be directly proportional to the resistance of the material used. Among copper and Nichrome, the resistance of nichrome wire is more compared to copper. Therefore the heat produced will be more in the case of nichrome wire.

Before you learn how to make a buzzer, you must know what a buzzer is. The buzzer is an electronic device that makes an audible sound when an external voltage is applied. The outcome of such a buzzer circuit results in a beeping or a buzzing sound. You must have come across a buzzer in different quiz competitions or game shows. Such machines are generally used in the tie-breaker rounds of the game. If you want to know how to make a buzzer circuit, you must first know what does a buzzer do.

The Functionality of a Buzzer

As stated earlier, a buzzer is an electronic device. It has a circuit being carefully designed in it. When the circuit is completed, the electric current flows through it and externally manifests as the buzzing sound. The circuit is connected to a diaphragm present inside the machine. When the voltage is applied to the machine, the diaphragm vibrates frantically, resulting in its sound. In the resting stage, the circuit is broken at the point of application of force. When an external force is enforced to the buzzer, such as pressing the buzzer button, the current passes through the circuit and activates the buzzer. 

The buzzer might be continuously active throughout the time the person presses the button. However, it might also have a mechanism to disrupt the circuit after some time automatically. In such a scenario, the buzzer will stop the sound even if the button is pressed for a long time. Such a mechanism will help save energy since the sound is generally required for a few seconds. 

What is a Buzzer Circuit?

The electrical circuit present inside a buzzer is called a buzzer circuit. If you wish to make the buzzer circuit at your home, you can use the armature as a key in the circuit. If you pull down the armature, the circuit gets disconnected. As a result, the nail will lose its magnetism field, bringing the armature back to the field again. The armature will move up and again close the circuit. As the circuit is completed, the entire cycle is completed. Such a cycle continues to take place repeatedly, and the buzzer will work. 

Creating a Flipper

Creating the flipper is the next step in the process of how to make a buzzer circuit. For this process, you need to have a bare copper wire, which you need to bend. This bent copper wire will act as a flipper. It is so-called since it will flip the circuit from the off position to the on position and vice versa. In most advanced buzzer making kits, such copper-based flippers were included. Otherwise, you have to use your own bare copper wire to make the flippers. Try to attach one end of the wire on the board while the other end on the armature top. You can use a screw for this purpose.

For connecting the buzzer, it is important to connect the red wire to the flipper screw. You will find the red wire connected to the battery holder. After connecting the red wire, connect the other wire attached to the armature to the key. This circuit will enable the electricity to pass through the armature and then enter the key.

Buzzer Test

After you have prepared the buzzer circuit, it is time to check the functionality of the buzzer. For that reason, you need to run the buzzer test. In this test, you need to push the key so that the circuit is connected. If you do not hear any buzzing sound, then you might need to perform some troubleshooting steps. Some of these steps include:

• Ensure that the flipper wire touches the armature when placed in the upward position.

• Also, ensure that the flipper wire does not touch the armature when placed in the downward position. 

• Consider all the connections and secure them wherever applicable. Make sure that there are no loose connections.

The above model is a simple description of how to make a buzzer circuit. Although the ones available in the market consider more complex mechanisms, this simple model will enable the students to learn a buzzer in a circuit. The students can follow such a model to make buzzers at home.

The hydraulic machines generally use a liquid fluid that is the power to perform work. Here, we will discover even more about it. The construction of vehicles is a common example. In this type of machine which is the hydraulic machine, the hydraulic fluid is pumped to various hydraulic motors and even to the hydraulic cylinders throughout the machine and then it becomes pressurized according to the resistance present. The fluid which we have just seen is controlled directly or we can do that automatically by controlling valves and distributing through hoses, tubes, or we can say pipes.

 

The system which is hydraulic is like pneumatic systems which are based on Pascal’s law which states that any pressure which is applied to a fluid that is inside a closed system will transmit that pressure equally everywhere and in all directions. A system like the hydraulic system uses an incompressible liquid as its fluid and rather than a compressible gas.

Hydraulic Machines and their Applications

Hydraulic Lifts: The hydraulic lift that we are discussing is an elevator that is operated by fluid pressure generated by a suitable fluid. It is generally used to raise automobiles in service stations and even in garages. In a hydraulic lift, two pistons are separated by the space which is filled with a liquid. A piston that is there is a small cross-section A1 is used to exert a force that is, say, F1 directly on the liquid. The pressure denoted by P =F/A is transmitted throughout the liquid to the larger cylinder which is in turn attached to a larger piston of area denoted as A2 which results in an upward force that is denoted by  P × A2.

 

Therefore, we can say that the piston is capable of supporting a large force that is the large weight of say a car or a truck that is placed on the platform.

 

By changing the force at an area that is A1 the platform can be moved up or down. Thus we can say that the applied force has been increased by a factor of A2/A1  and this factor is the mechanical advantage that is of the device.

 

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Hydraulic Brakes: The breakers which are called the hydraulic brake are an arrangement of the braking mechanism in which suitable brake fluid is used to transfer pressure from the control mechanism to the mechanism of the brake. Hydraulic brakes in automobiles also work on the same principle. When we apply a little bit of force to the pedal with our foot then the master piston moves inside the master cylinder and after that, the pressure caused is transmitted through the brake oil which is to act on a piston of the larger area. A large force generally acts on the piston and is pushed down and is now expanding the brake shoes against the brake lining. In this way, we have seen that a small force on the pedal produces a large retarding force on the wheels.

 

 An important advantage of the system of hydraulic brakes is that the pressure set up by pressing a pedal is transmitted equally to all cylinders that are generally attached to the four wheels so that the braking effort is equal on all the wheels.

 

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To learn more about hydraulic machinery and other related topics we could simply go to some of the videos of our site .com. 

 

Hydraulic Machines Uses

The application of hydraulics in everyday life has become so normal to people that nobody ever thinks about it anymore but still, we can say that we will see it here.

• Today as we know virtually in every industry we see the use of hydraulics to move machinery and equipment to accomplish various tasks including tractors in agriculture. Some more examples are cranes in building & construction and forklift in manufacturing and production warehouses braking in transportation and many more.

• The hydraulic machines utilize hydraulic fluid pressure to primarily power movement or we can say that as a basic source of energy.

• The Hydraulic machines also include dumps trucks and the aluminum extruders or the plastic extruders and cranes along with the jackhammers and hose crimpers.

Here we have discussed how hydraulics help in accomplishing various day-to-day tasks across industries and sectors.

 

Hydraulics in Everyday Life

In the field of jobs performed by hydraulic machines, we may also include metal stamping and hose crimping, injection molding, and many more.

 

Entertainment – we can say here that spinning motors are a great source of entertainment in amusement parks. They apply hydraulics technology which is to power rides and then later provides motion, for instance, a Ferris wheel.

 

Vehicle Braking – Virtually all vehicles on the road are powered by hydraulics. Specifically, if we look at the brake fluid which is an important component of a vehicle’s braking system. The Pressing of the foot on the brake pedal forces a rod and piston which is within the master cylinder to move and achieve the desired effect which ideally involves slowing down or we can also say stopping the vehicle.

 

Lifting and Repair & Maintenance – As we know, without a hydraulic system it would be very difficult to lift a very heavy motor vehicle to facilitate repair and maintenance. The system generally uses hydraulic fluid to help lift any heavy load to the desired height.

 

Construction – The construction industry has greatly benefited from technological advancements due to hydraulics. 

 

Benefits of Solving important Questions

As students must be aware that Class 11 is the basis for Class 12 as well as for the entrance exams. Practice is one way to ensure that students secure good marks in their exams. Important questions are available to students online as well as in reference books. These important questions are curated by experts who are the finest in their field of the subject. These important questions are availed to students after thorough research on the latest ex patterns and previous year’s question paper. When students will attempt these questions and solve them, it will ensure students are preparing effectively for their exams. By solving these questions students will get conceptual clarity by chapters and will clear their doubts.  The set of important questions covers all crucial and necessary topics within a chapter. Going through important questions boosts up students’ confidence and there is a high stake that some of these questions might be asked in the examinations. Students can also refer to the CBSE Class 11 important questions to get a fair idea about the structure of the paper.

 

Students will enjoy the following benefits as they will solve more and more important questions:

• As students will solve they will observe and understand the topics from which the questions are mostly asked. It will help students to frame more questions from those topics.

• Solving important questions will give students a reality check about their speed while answering the questions and develop impressive time management skills for final exams.

• Attempting these important questions is a good semi mock test to get acquainted with the difficulty level of questions and improve their problem-solving skills.

• Increases students’ capability to understand and solve any type of question during the examinations.

Induced electromotive current is the induction of current in the loop just by changing the magnetic field. In Faraday’s law, there are some experiments which are based on this theory. In the first experiment, we have noticed that the ammeter shows zero current reading which generally means or proves that a stationary magnet does not induce a current in a coil. In the second experiment, we have noticed that the meter shows the induction the current which demonstrates that it is due to the change in the magnetic field as the magnet is moved towards or we can say away from the coil.

So it is very clear to us that a constant magnetic field generally does nothing to the coil while we can say that a changing field causes current to flow.

Hence we can gain an observation from the above experiments that we have discussed that only by changing a magnetic field we can make the current flow. To be more accurate we can say that if the magnetic flux through a coil is changed then a voltage will be produced. This voltage is called the induced emf. 

Based on his understanding of electromagnets we can say that he expected that when current started to flow in one wire a sort of wave would travel through the ring and then cause some electrical effect on the opposite side. He plugged one wire that too into a galvanometer and then watched it as he connected the other wire to a battery as well. He saw a transient current which he for himself called as a “wave of electricity“. when he connected the wire with the battery and another when he disconnected it. Within two months the scientist named Faraday found several other manifestations of electromagnetic induction. 

Induced Electromotive Force

The Magnetic flux is generally linked with the surface area when it is held inside the magnetic field. We can say that when the direction of the magnetic field is perpendicular to the surface area then the flux of magnet or we can say that the magnetic flux on the surface is more. When the magnetic field is said to be parallel to the surface area, then the magnetic flux is on the surface which is less.

Have you ever wondered that when the coil completely remains inside the magnetic field that too during motion then why no current flows through it?

When the coil is said to be entirely inside the magnetic field, one of the two ends of the coil becomes positive and the other end of the coil becomes negative. The potential difference which is between the coils will be equal in each case. So when two cells that are having equivalent electromotive force are connected to each other then we can say that no current flows through the coil, and no net induced electromotive force exists in the coil.

The law of Lenz’s describes the direction which is of the induced field. 

Induced Electromotive Force and Current

Faraday’s law that generally describes two different phenomena that is the motional EMF generated by a force which is the magnetic force on a moving wire and the transformer that is of the EMF this is generated by an electric force due to a changing magnetic field that too due to the differential form of the Maxwell–Faraday equation. In 1861, James Clerk Maxwell drew attention to this separate physical phenomena. This is believed or said to be a unique example in physics of where such a fundamental law is invoked to explain two such different phenomena.

Do You Know?

What happens when the string of the electric guitar which we use to play vibrates? 

When the string of an electric guitar vibrates then we can say that an electromotive force is introduced in the coil. The induced magnetization which is present in the string is picked up from the vibration of the guitar. The input which is of an amplifier that is of the guitar is connected to the two ends of the coil which are connected to the speakers.

Stay tuned to to learn more about emf, induced electromotive force, and much more.

Motion is the change with time of the position or orientation of a body. Everything in this universe is in a state of continuous movement, for example, the motion of animals and humans. Besides this, the basic particle of a matter a.k.a the atom is also in the state of continuous motion too. By this, we mean that every single physical procedure in this universe possesses some type of motion, and the motion either be slow or fast, but it is always present.

You can find objects moving everywhere. The motion of animals and humans are everyday examples of motion. The basic particle of a matter, i.e., the atom is in the state of continuous motion too. Every single physical procedure in this universe is made up of some type of motion. It can be either slow or fast, but the motion is present. However, if a man is snoring, do we say he is in motion or the chirping birds resting on the tree are in motion? If not, then how do we define the movement in an object or a living? 

So, how do you define that there is movement in an object? You identify any movement in the object when you compare its new position from the original position. Any change in the position of the object, with respect to time, is considered to be a motion. There are several things that you can see moving while certain objects like Earth that appear to be still, is also in motion in an actual sense. Everything on Earth that appears still is actually in motion as the Earth itself is in motion (i.e, Rotation and Revolution). This page will help us briefly identify the difference between resting and motion and also the types of motion along with illustrating examples.

How to Identify an Object/Body in Motion?

It’s pretty clear from the above text that we can determine any movement in the object by comparing its new position from the original position. Any change in the position of the object, with respect to time, is considered to be a motion. We find several things that keep on moving like Earth that appears to be still, is always in motion in an actual sense. Everything on Earth that appears still is actually in motion as the Earth itself is in motion (i.e., Rotation and Revolution).

How to Determine if the object is in Motion: Parameters in Motion

An orange fell from a tree, water flowing from the tap, or rattling windows, all these show that the object is in motion. Now, let us see the following important terms that will help us in determining motion:

• Distance 

• Speed

• Displacement

• Time

Please note that the distance and displacement both help us in describing the change in the object’s position. Also, the distance travelled by an object from point A to point B depends on the type of path it has taken. This means that for an object that takes a circular path, the distance covered by it on this path will be different from the distance covered in the case of a linear path. 

In the case of displacement, it is defined as the shortest distance that connects the two points, P and Q (basically initial and final point). So, let us say P and Q are two cities. The distance between them is ‘d’. Now, when a person moves from city P to city Q and then again returns back to city P, then

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So, let us say, you are travelling from city P to Q. The distance between them is ‘d’. Now, when you move from city Q and return back to city P, then

Distance travelled = d (P to Q) + d (Q to P)

Displacement = 0, as there is no difference in your initial and final position, i.e, P and P. As you started from P and returned back to P.So, in this case, displacement is nil. 

Besides this, we know that the speed of an object/body is the rate at which the position of the object changes with respect to its origin. It is measured as distance (in meters)/ Time (in seconds) or m/s. This is how we describe the motion of an object. Now, let us go through the types of motion.

Types of Motion

Now, let us talk about the distinctive types of motions that may be seen in an object. These are Linear, Rotary, Oscillating motion, and Periodic motion. Each of these kinds is carried out with an exclusive mechanical means. Let us analyze more about them in detail. 

1) Linear Motion

In linear motion, the object moves from one position to another in either a curved direction or a straight line. On the premise of the type of direction taken by an object, linear motion is similarly categorized as: 

• Rectilinear Motion – Here, the route taken by an object is a straight line.

• Curvilinear Motion – Here, the route taken by the object is curved.

One of the nice examples of linear motion is linear actuators in which you could locate cars, cycles, trains, and different cars travelling in a single straight direction. But it will not be referred to as a linear motion whilst the road or rail track is flawlessly circular. You may even locate linear cylinders that display linear motion in pneumatic, hydraulic, and electric options. A linear motion has loads of importance in the field of manufacturing, automation, robotics, etc.

2) Rotary Motion

Rotary motion is a sort of motion in which the object moves in a circle. This kind of motion happens whilst an object rotates at its own place or axis. The rotary motion turned into the first kind of motion that was invented by scientists in primitive times. Some of the examples that could assist you to understand the rotatory motion are:

• Earth rotating on its own axis about the sun is a nice instance of rotary motion.

• Another instance is the motion of the wheels and steering wheel of the automobile in the driving state. You will locate that each is rotating around its own axis. The same thing goes with the engine of the automobile because it additionally moves on its own location. Similar to linear cylinders, these days rotary actuators are notably utilized in diverse industries. These cylinders are available for pneumatic, electric, and hydraulic options.

3) Oscillatory Motion

This is the third kind of motion that is characterised by the motion of the item in the form of front and back oscillation. In different words, an oscillatory motion is described as the motion of an object around its mean position. If an object repeats the cycle of its motion after a particular time period, then it far seems like an oscillating motion.

One of the nice examples of oscillating motion is the pendulum of a clock. It repeats its motion after a certain time frame. In an actual sense, the pendulum isn’t displaced from its role. It is stationary in a single position, but it shows motion. Such a kind of recurring motion after a certain time period is known as an oscillating motion.

In this sort of motion, the motion of the object is called oscillation. This is due to the repeated nature of the motion that takes place after a fixed time period. A few different illustrations of an oscillating motion are:

• When an infant oscillates backwards and forwards around its fixed position at the swing.

• Table fan is some other instance of periodic motion.

• Both linear, in addition to a rotary actuator, have oscillating motion.

• Waves Sound waves are the result of the oscillation of particles.

• When the cords of the sitar or guitar are struck, then they move backwards and forward approximately their mean position (i.e, oscillatory motion).

4) Periodic Motion

Periodic motion is a kind of motion that is repeated at the same time intervals. A few examples of this motion are a bouncing ball, a rocking chair, a swing in motion, a water wave, a vibrating tuning fork, etc. From the text on motion – types of motion and definition, we understand that motion of an object is the change in orientation/position of a body with respect to time and this change can be slow or fast (speed).