A piece of wire of resistance 'R' is cut lengthwise into three identical parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R', then the value of R/R' is :
A piece of wire of resistance 'R' is cut lengthwise into three identical parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R', then the value of R/R' is :
Options
Official answer
When a piece of wire of resistance R is cut lengthwise into three identical parts, the resistance of each part will be R/3. When these parts are connected in parallel, the equivalent resistance R' is given by 1/R' = 1/(R/3) + 1/(R/3) + 1/(R/3) = 3/(R/3) = 9/R. Therefore, R/R' = 9.
Marking scheme
- 1.1 mark for correct answer
Hint
Use the formula for equivalent resistance in parallel circuits: 1/R' = 1/R1 + 1/R2 + 1/R3.
Quick oral answer
The value of R/R' is 9.
Common mistakes
- 1.Incorrect calculation of equivalent resistance
Analysis and explanation
This problem requires the application of the concept of equivalent resistance in parallel circuits. The correct answer is 9, which is obtained by calculating the equivalent resistance R' and then finding the ratio R/R'.
Interesting facts
The concept of equivalent resistance is important in electrical engineering and electronics.
Question details
Q12 of 39 questions
- Board
- CBSE
- Class
- Class 10
- Subject
- Science
- Year
- 2025
- Section
- Section A
- Marks
- 1
- Type
- MCQ
- Chapter
- Electricity
- Topic
- Electricity
- Bloom's level
- Remembering
- Syllabus topic
- Electricity
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Frequently asked questions
How many marks does this question carry in CBSE Class 10 Science 2025?
This question carries 1 mark in the CBSE Class 10 Science 2025 examination.
Which chapter does this question come from in Science?
This question is from the chapter "Electricity" in the CBSE Class 10 Science syllabus.
What topic does this question cover in Science?
This question covers the topic "Electricity" from CBSE Class 10 Science.
What type of question is this in the CBSE Class 10 Science 2025 paper?
This is a MCQ question from Section A in the CBSE Class 10 Science 2025 paper.