Alternating Current
Alternating Current
Direct Current (DC) : An electric current whose magnitude is either constant or variable but the direction of flow in a conductor remains the same is called direct current. It is denoted by DC. Sources of DC are voltaic cell, a dry cell, battery, DC generator, etc.
Alternating Current (AC): An electric current whose magnitude changes with time -and direction reverses periodically is called alternating current. It is denoted by AC.
Sources of AC are hydro-electric generators, thermal power generators and nuclear power generators, etc.
Suppose you connect a bulb to an AC source such as the AC supply of your house (Figure 5.23a),
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The potential difference VA - VB across the bulb keeps changing with time. When the current flows from A to B in the bulb, VA > VB . When the current flows from B to A in the bulb, VA < VB. When the current becomes momentarily zero before changing direction, VA = VB.
In fact, the potential difference across the bulb changes gradually from a maximum value Vo, to zero and then to the minimum value -Vo From -Vo it increases to zero before reaching Vo. once again. The way the potential difference (voltage) across the bulb changes with time is shown in figure.
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A plot of the alternating current through the bulb will also be similar. The number of cycles completed by the AC in one second is called the frequency of AC. Starting from a particular value (say, maximum or minimum), when the current or voltage reaches the same value next time, it is said to complete one cycle. If it completes 1 cycle in one second, we say that its frequency is 1 hertz (Hz). The frequency of our household AC supply is 50 Hz, i.e., there are 50 cycles per second, which means that AC changes its polarity after every 100th part of a second as it changes its polarity twice in one cycle. or we can say it changes direction 100 times in 1 second.
The major difference between AC and DC is that DC always flows in one direction, while AC reverses its direction periodically. The advantage of AC over DC is that electric power can be transmitted over long distances without much loss of energy.
When we connect the bulb to an AC source the potential difference VA - VB across the bulb keeps_____________with time. | |||
| Right Option : B | |||
| View Explanation | |||
The way the potential difference (voltage) across the bulb changes with time is shown in which of the following figure? | |||
| Right Option : A | |||
| View Explanation | |||
AC current is known as a _______________ | |||
| Right Option : A | |||
| View Explanation | |||
Students / Parents Reviews [20]
About Abhyas metholodology the teachers are very nice and hardworking toward students.The Centre Head Mrs Anu Sethi is also a brilliant teacher.Abhyas has taught me how to overcome problems and has always taken my doubts and suppoeted me.
Shreya Shrivastava
8thThe experience was nice. I studied here for three years and saw a tremendous change in myself. I started liking subjects like English and SST which earlier I ran from. Extra knowledge gave me confidence to overcome competitive exams. One of the best institutes for secondary education.
Aman Kumar Shrivastava
10thWe started with lot of hope that Abhyas will help in better understnding of complex topics of highers classes. we are not disappointed with the progress our child has made after attending Abhyas. Though need to mention that we expected a lot more. On a scale of 1-10, we would give may be 7.
Manya
8thA marvelous experience with Abhyas. I am glad to share that my ward has achieved more than enough at the Ambala ABHYAS centre. Years have passed on and more and more he has gained. May the centre flourish and develop day by day by the grace of God.
Archit Segal
7thUsually we see institutes offering objective based learning which usually causes a lag behind in subjective examinations which is the pattern followed by schools. I think it is really a work of planning to make us students grab the advantages of modes of examination, Objective Subjective and Onli...
Anika Saxena
8thAbhyas is an institute of high repute. Yogansh has taken admission last year. It creates abilities in child to prepare for competitive exams. Students are motivated by living prizes on basis of performance in Abhyas exams. He is satisfied with institute.
Yogansh Nyasi
7thWhen I have not joined Abhyas Academy, my skills of solving maths problems were not clear. But, after joining it, my skills have been developed and my concepts of science and SST are very well. I also came to know about other subjects such as vedic maths and reasoning.
Sharandeep Singh
7thIt was a good experience with Abhyas Academy. I even faced problems in starting but slowly and steadily overcomed. Especially reasoning classes helped me a lot.
Cheshta
10thMy experience with Abhyas academy is very nice or it can be said wonderful. I have been studying here from seven class. I have been completing my journey of three years. I am tinking that I should join Abhyas Academy in tenth class as I am seeing much improvement in Maths and English
Hridey Preet
9thIn terms of methodology I want to say that institute provides expert guidence and results oriented monitering supplements by requsite study material along with regular tests which help the students to improve their education skills.The techniques of providing education helps the students to asses...
Aman Kumar Shrivastava
10thI have spent a wonderful time in Abhyas academy. It has made my reasoning more apt, English more stronger and Maths an interesting subject for me. It has given me a habbit of self studying
Yatharthi Sharma
10thMy experience with Abhyas is very good. I have learnt many things here like vedic maths and reasoning also. Teachers here first take our doubts and then there are assignments to verify our weak points.
Shivam Rana
7thAbhyas is a complete education Institute. Here extreme care is taken by teacher with the help of regular exam. Extra classes also conducted by the institute, if the student is weak.
Om Umang
10thMy experience was very good with Abhyas academy. I am studying here from 6th class and I am satisfied by its results in my life. I improved a lot here ahead of school syllabus.
Ayan Ghosh
8thAbhyas Methodology is very good. It is based on according to student and each child manages accordingly to its properly. Methodology has improved the abilities of students to shine them in future.
Manish Kumar
10thAbhyas institute is one of the best coaching institute in the vicinity of Ambala cantt.The institute provides good and quality education to the students.The teachers are well experienced and are very helpful in solving the problems. The major advantages of the institute is extra classes for weak...
Shreya Shrivastava
8thIt was good as the experience because as we had come here we had been improved in a such envirnment created here.Extra is taught which is beneficial for future.
Eshan Arora
8thAbhyas is good institution and a innovative institute also. It is a good platform of beginners.Due to Abhyas,he has got knoweledge about reasoning and confidence.My son has improved his vocabulary because of Abhyas.Teacher have very friendly atmosphere also.
Manish Kumar
10thThird consective year,my ward is in Abhyas with nice experience of admin and transport support.Educational standard of the institute recumbent at satisfactory level. One thing would live to bring in notice that last year study books was distributed after half of the session was over,though study ...
Ayan Ghosh
8thAbhyas institute is one of the best coaching institute in the vicinity of Ambala Cantt area. The teachers of the institute are well experienced and very helpful in solving the problems of the students.The good thing of the institute is that it is providing extra classes for the students who are w...
