Electrical Engineering (EE) Exam > Electrical Engineering (EE) Questions > If the current through a moving iron instrume... Start Learning for Free
If the current through a moving iron instrument is increased by 20%, what is the percentage increase in the deflection torque?
- a)40
- b)25
- c)32
- d)44
Correct answer is option 'D'. Can you explain this answer?
Most Upvoted Answer
If the current through a moving iron instrument is increased by 20%, w...
Increase in current through a moving iron instrument and the percentage increase in deflection torque are related through a mathematical equation. To find the percentage increase in deflection torque, we need to understand the relationship between the current and deflection torque.
The deflection torque in a moving iron instrument is given by the equation:
T = K * I^2
where T is the deflection torque, K is a constant, and I is the current passing through the instrument.
Let's say the initial current passing through the instrument is I1, and the final current after the increase is I2. The initial deflection torque is T1, and we need to find the percentage increase in deflection torque.
- Identify the given information:
- Initial current: I1
- Increase in current: 20%
- Final current: I2 = I1 + 0.2 * I1 = 1.2 * I1
- Initial deflection torque: T1
- Percentage increase in deflection torque: ?
- Calculate the final deflection torque:
- Substitute the values in the equation: T2 = K * (1.2 * I1)^2 = 1.44 * K * I1^2
- Calculate the percentage increase in deflection torque:
- Percentage increase = (T2 - T1) / T1 * 100%
- Substitute the values: (1.44 * K * I1^2 - K * I1^2) / K * I1^2 * 100%
- Simplify: 0.44 * 100% = 44%
Hence, the percentage increase in the deflection torque is 44%. Therefore, the correct answer is option D.
The deflection torque in a moving iron instrument is given by the equation:
T = K * I^2
where T is the deflection torque, K is a constant, and I is the current passing through the instrument.
Let's say the initial current passing through the instrument is I1, and the final current after the increase is I2. The initial deflection torque is T1, and we need to find the percentage increase in deflection torque.
- Identify the given information:
- Initial current: I1
- Increase in current: 20%
- Final current: I2 = I1 + 0.2 * I1 = 1.2 * I1
- Initial deflection torque: T1
- Percentage increase in deflection torque: ?
- Calculate the final deflection torque:
- Substitute the values in the equation: T2 = K * (1.2 * I1)^2 = 1.44 * K * I1^2
- Calculate the percentage increase in deflection torque:
- Percentage increase = (T2 - T1) / T1 * 100%
- Substitute the values: (1.44 * K * I1^2 - K * I1^2) / K * I1^2 * 100%
- Simplify: 0.44 * 100% = 44%
Hence, the percentage increase in the deflection torque is 44%. Therefore, the correct answer is option D.
Free Test
FREE
| Start Free Test |
Community Answer
If the current through a moving iron instrument is increased by 20%, w...
Concept:
In moving iron instruments, the deflecting torque is unidirectional (acts in the same direction) whatever may be the polarity of the current.
The deflecting torque is given by
Where,
I is operating current
L is self-inductance
θ is deflection
Td ∝ I2
So that the deflection torque of the moving iron instrument is proportional to the square of the RMS value of the operating current and change in self-inductance.
In moving iron instruments, the deflecting torque is unidirectional (acts in the same direction) whatever may be the polarity of the current.
The deflecting torque is given by
Where,
I is operating current
L is self-inductance
θ is deflection
Td ∝ I2
So that the deflection torque of the moving iron instrument is proportional to the square of the RMS value of the operating current and change in self-inductance.
Calculation:
When the current through a moving iron instrument is increased by 20%, then deflection torque is
∴ T'd = 1.44 Td
Hence deflection torque is increased by 44%
When the current through a moving iron instrument is increased by 20%, then deflection torque is
∴ T'd = 1.44 Td
Hence deflection torque is increased by 44%
 | Explore Courses for Electrical Engineering (EE) exam |  |
Top Courses for Electrical Engineering (EE)View all
Top Courses for Electrical Engineering (EE)
Question Description
If the current through a moving iron instrument is increased by 20%, what is the percentage increase in the deflection torque?a)40b)25c)32d)44Correct answer is option 'D'. Can you explain this answer? for Electrical Engineering (EE) 2026 is part of Electrical Engineering (EE) preparation. The Question and answers have been prepared according to the Electrical Engineering (EE) exam syllabus. Information about If the current through a moving iron instrument is increased by 20%, what is the percentage increase in the deflection torque?a)40b)25c)32d)44Correct answer is option 'D'. Can you explain this answer? covers all topics & solutions for Electrical Engineering (EE) 2026 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for If the current through a moving iron instrument is increased by 20%, what is the percentage increase in the deflection torque?a)40b)25c)32d)44Correct answer is option 'D'. Can you explain this answer?.
If the current through a moving iron instrument is increased by 20%, what is the percentage increase in the deflection torque?a)40b)25c)32d)44Correct answer is option 'D'. Can you explain this answer? for Electrical Engineering (EE) 2026 is part of Electrical Engineering (EE) preparation. The Question and answers have been prepared according to the Electrical Engineering (EE) exam syllabus. Information about If the current through a moving iron instrument is increased by 20%, what is the percentage increase in the deflection torque?a)40b)25c)32d)44Correct answer is option 'D'. Can you explain this answer? covers all topics & solutions for Electrical Engineering (EE) 2026 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for If the current through a moving iron instrument is increased by 20%, what is the percentage increase in the deflection torque?a)40b)25c)32d)44Correct answer is option 'D'. Can you explain this answer?.
Solutions for If the current through a moving iron instrument is increased by 20%, what is the percentage increase in the deflection torque?a)40b)25c)32d)44Correct answer is option 'D'. Can you explain this answer? in English & in Hindi are available as part of our courses for Electrical Engineering (EE). Download more important topics, notes, lectures and mock test series for Electrical Engineering (EE) Exam by signing up for free.
Here you can find the meaning of If the current through a moving iron instrument is increased by 20%, what is the percentage increase in the deflection torque?a)40b)25c)32d)44Correct answer is option 'D'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of If the current through a moving iron instrument is increased by 20%, what is the percentage increase in the deflection torque?a)40b)25c)32d)44Correct answer is option 'D'. Can you explain this answer?, a detailed solution for If the current through a moving iron instrument is increased by 20%, what is the percentage increase in the deflection torque?a)40b)25c)32d)44Correct answer is option 'D'. Can you explain this answer? has been provided alongside types of If the current through a moving iron instrument is increased by 20%, what is the percentage increase in the deflection torque?a)40b)25c)32d)44Correct answer is option 'D'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice If the current through a moving iron instrument is increased by 20%, what is the percentage increase in the deflection torque?a)40b)25c)32d)44Correct answer is option 'D'. Can you explain this answer? tests, examples and also practice Electrical Engineering (EE) tests.
| Explore Courses for Electrical Engineering (EE) exam | |
Top Courses for Electrical Engineering (EE)
Explore Courses
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
