For magnetic field produced by a toroid we have two formulae:
1)B=permeability of free spacexnxi-for a normal toroid
2)B=(permeability of free spacexnxi)/2xpixr-for a toroid made from infinitely long solenoid.
Which formula is to be used when the nature of the toroid i,e,.whether finite or infinite is not
clearly mentioned in the question?
Asked by Chandropal Parashor | 11th Jul, 2014, 06:55: AM
A toroid is nothing but a solenoid bent into a circular shape.
Also the term "n" in the two formulae that you have provided are not the same.
For a toroid, the ideal formula for any question is
Where, N is the total number of turns of the toroid.
The second formula is a comparison with the solenoid which is given as
Where, is the number of turns per unit length.
Hence, ideally both the formulae are correct.
If in the question the nature is not mentioned, then look for the words "Number of turns" or "Number of turns per unit length", and then use the appropriate formula.
If it says "Number of turns", then use the formula (1) and if it says "Number of turns per unit length", then use the formula (2).
Answered by Romal Bhansali | 11th Jul, 2014, 09:51: AM
- 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?
- How net current on a toroid is zero???
- What is self inductance ?
- Derive the formula for self inductance of a solenoid ?
- What is mutual induction?
- A toroid coil has 1000 turns and diameter of 30 cm with the area of cross section of 2 cm2. Calculate i) inductance of coil ii) induced e.m.f when the a current of 2 A is reversed in 0.03 secs.
- What is the unit of Self Inductance? Define.
- What is the length of a solenoid with total number of turns 1000, area of cross section 20 cm2 and self inductance of 4.02 × 10-3 H.
- If the current of 8 A in the primary circuit is reduced to 0 at a uniform rate in 10-2 secs. What is the induced e.m.f when the coefficient of mutual inductance is 4H?
- On what factors does the coefficient of mutual induction depends?
Kindly Sign up for a personalised experience
- Ask Study Doubts
- Sample Papers
- Past Year Papers
- Textbook Solutions
Verify mobile number
Enter the OTP sent to your number