LIVE Course for free

Rated by 1 million+ students
Get app now
JEE MAIN 2023
JEE MAIN 2023 TEST SERIES
NEET 2023 TEST SERIES
NEET 2023
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
0 votes
52 views
in Electronics by (30.0k points)
closed by
Current flowing in a circuit is i = (18 + 10sinωt + 7sin2ωt). A moving iron ammeter is connected in the circuit to measure this current. The reading of the meter will be approximately
1. 28 A
2. 35 A
3. 18 A
4. 20 A

1 Answer

0 votes
by (30.0k points)
selected by
 
Best answer
Correct Answer - Option 4 : 20 A

Moving iron (MI) instruments always measures the RMS value of a given quantity.

RMS (Root mean square) value:

  • RMS value is based on the heating effect of wave-forms.
  • The value at which the heat dissipated in AC circuit is the same as the heat dissipated in DC circuit is called RMS value provided, both the AC and DC circuits have equal value of resistance and are operated at the same time.

Calculation:

Given:

Current = i(t) = (18 + 10 sin ωt + 7 sin 2ωt)

RMS value of current = \( \sqrt {{{18}^2} + (\frac{{{10}}}{\sqrt2})^2 +( \frac{{{7}}}{\sqrt2}}) ^2\) = 19.962 A ≈ 20 A

  • Moving coil instrument (PMMC) always measures the average value of the signal provided.
  • PMMC instruments are suitable for measuring only DC quantities whereas MI instruments are suitable for measuring both AC and DC quantities.

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...