Find the initial angular acceleration of the coil just after the current is started.

Shown in the following figure is a long, straight wire and a single-turn rectangular loop, both of which lie in the plane of the page. The wire is parallel to the long sides of the loop and is 0.5 m away from the closer side. At an instant when the voltage induced in the loop is 2.5 V, what is the time rate of change of the current in the wire? 0.50 m] 3.0 m 0.50 m a. What is the expression for magnetic field B due to the current I in the long, straight wire, at distance r away from the wire? B = . Give your answer in terms of given variables (I, r) and physical and numerical constants (o, T, ke, and/or c). Spell out Greek letters and use underscore ("_") for subscripts. b. Because the magnetic field is not uniform, you will have to use integration to calculate the magnetic flux, = = [₁ BdA. Find the magnetic flux through the loop as a function of I ( will be proportional to I, as shown below; find the coefficient, in base SI units). Hint for (b) Φ I. Give your answer in terms of given…

Magnetic field lines can be entirely confined within the core of a toroid, but not within a straight solenoid. Why?

Two concentric solenoids carry currents in opposite directions. The inner solenoid has 50 turns per centimetre, the outer solenoid 20 turns per centimetre. The inner coil carries a current of 0.80-A. (a) Calculate the current needed in the outer coil so that its field cancels the field produced by the inner coil. (b) How large a field is produced by the inner coil?