Ask a Doubt
Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 12-science Answered

Q)Show that a planar loop carrying a current I, having N closely wound turns and area of cross section A, possesses a magnetic         moment m=NIA.
Asked by Ibrahim Mohammed | 14 Feb, 2016, 05:35: PM
answered-by-expert Expert Answer
Consider a plane loop of wire carrying current.
Looking at the upper face, current is anticlockwise. Therefore, it has a North polarity. Looking at the lower face of the loop, current is clockwise. Therefore, it has a South polarity. The current carrying loop thus behaves as a system of two equal and opposite magnetic poles and hence is a magnetic dipole.
The magnetic dipole moment of the current loop (M) is directly proportional to strength of the current (I) through the loop and the area enclosed by the loop.
i.e., begin mathsize 14px style straight M proportional to straight I space space space and space space straight M proportional to straight A therefore straight M equals KIA space space space space... space left parenthesis 1 right parenthesis end style
where K is a constant of proportionality.
If we define unit magnetic dipole as that of a small one turn loop of unit area carrying unit current, then from eqn (1),
1 = K × 1 × 1   or K = 1
Therefore, from eqn (1),  M = IA
For N such turns, M = NIA   ... (2)
Note: Eqn (2) is valid for planar current loop of any shape and size.
Answered by Faiza Lambe | 15 Feb, 2016, 03:12: PM

Concept Videos

Multiple Choice Questions Practice Test
Answered Unanswered My Questions My Answers
CBSE 12-science - Physics
state biot savart law
Asked by himanshurawat5823 | 08 Mar, 2024, 01:24: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Answer this:  Assertion (A): When radius of a circular loop carrying a steady current is doubled, its magnetic moment becomes four times.  Reason (R): The magnetic moment of a circular loop carrying a steady current is proportional to the area of the loop.  Select the correct answer from the codes (a), (b), (c) and (d) as given belote.  (a) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of the Assertion (A).  (b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of the Assertion (A).  (c) Assertion (A) is true, but Reason (R) is false.  (d) Assertion (A) is false and Reason (R) is also false.
Asked by anubhutiupadhaya | 06 Mar, 2023, 04:23: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
PLEASE SOLVE IT
question image
Asked by rd0543293 | 19 Jun, 2022, 10:51: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
How much energy is stored in a 3 cm diameter, 12 cm long solenoid that has 200 turns of wire and carries a current of 0.8A?
Asked by arjunsah797 | 26 Mar, 2022, 09:10: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Please refer to the uploaded image for the doubt
question image
Asked by arjunsah797 | 16 Mar, 2022, 02:07: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
ampere law
Asked by shantanumail24 | 09 Mar, 2022, 07:04: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
As we know, work done by Magnetic force is always zero in moving a charged particle./So it cannot change speed of charged particle. MY doubt is that, can magnetic force change direction of motion of charged particle?
Asked by yashrajgharte24.12dgatl | 25 Oct, 2021, 06:53: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
the rate of change of potential difference across capacitor is 5×10^2 v/s . if capacitance is 2uF ,then displacement current between it's plate is ?
Asked by pushpakumari291279 | 01 Oct, 2021, 11:08: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
Sir , if a magnetic field is increasing in a cylindrical volume at a constant rate. then what will be direction of instantaneous acceleration experienced by an electron placed inside cylinder but not on center?
Asked by yashrajgharte24.12dgatl | 24 Sep, 2021, 04:21: PM
ANSWERED BY EXPERT ANSWERED BY EXPERT
CBSE 12-science - Physics
why the flux of magnetic field over a closed surface always zero?
Asked by yashrajgharte24.12dgatl | 24 Aug, 2021, 07:23: AM
ANSWERED BY EXPERT ANSWERED BY EXPERT
My Class Videos Tests ₹ Plans Ask a Doubt
Get Latest Study Material for Academic year 24-25 Click here
×