Ampere's Law, Cylinders, Solenoid & Toroid
Choose the WRONG Statement from the following statements.
(A) A toroid is a solenoid bent in the form of a closed ring.
(B) The magnetic field lines of solenoid are straight lines parallel to the axis inside the solenoid. (C) The magnetic field lines of toroid are circular having common centre.
(D) Inside a solenoid, magnetic field may be made strong by passing small current and using laminated coil of soft iron.
Show answer and solution
Answer: (a)
- (A) True: a toroid is a solenoid bent into a closed ring.
- (B) True: inside a long solenoid the field lines are straight and parallel to the axis.
- (C) True: field lines in a toroid are concentric circles.
- (D) Wrong: a strong field needs a large current (and a soft iron core), not a small current.
- So the wrong statement is D, answer (a).