The resistance of ohmic circuit elements such as metal wires or carbon resistor depends on the length of the wire. To find dependence,we will follow the following steps
1 Keep the thickness of the wire as fixed and just increase or decrease the length of the wire.
2. Apply a potential difference across the ends of the wire and calculate the value of R from the values of current and potential difference
3. Calculate the value of R for different values of the length of the wire.
4. Plot a graph as shown below by taking length along x axis and resistance along y axis
From the graph we observe that as length increases the resistance also increases. So we find that there is a proportionality between the length L of the wire and the resistance of the wire R. The resistance of a conductor R is directly proportional to its length l
i.e.
Since, the resistance of a wire is directly proportional to its length, i.e. when the length of the wire is doubled or halved, then its resistance also gets doubled or halved.
Illustration: In a circuit when a current of 5 A flows through a certain wire having resistance R a potential difference of 10 V is generated across the wire. What will be the new potential difference generated across the wire if the length of the wire is doubled.
Solution: It is given that
V= 10 V
I = 5 A
R= ?
V= IR
As the length of the wire is doubled so the resistance will be doubled.
So new potential difference of 20V is generated across the wire if the length of the wire is doubled.
A circular conductor is made of a uniform wire of resistance ohm/metre and the diameter of this circular conductor is 2 metres. Then the resistance measured between the ends of the diameter is (in ohms)- | |||
Right Option : C | |||
View Explanation |
__________ is a constant factor that depend on the nature of a conductor material. | |||
Right Option : D | |||
View Explanation |
A constant voltage is applied between the two ends of a uniform metallic wire. If both the length and radius of wire are doubled the: | |||
Right Option : A | |||
View Explanation |
Abhyas 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.
I 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
My experience with Abhyas academy is very good. I did not think that my every subject coming here will be so strong. The main thing is that the online tests had made me learn here more things.
It has a great methodology. Students here can get analysis to their test quickly.We can learn easily through PPTs and the testing methods are good. We know that where we have to practice
Abhyas 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.
It 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.
My 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.
Being a parent, I saw my daughter improvement in her studies by seeing a good result in all day to day compititive exam TMO, NSO, IEO etc and as well as studies. I have got a fruitful result from my daughter.
A 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.
My 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.