Consider a solenoid of length L, N windings, and radius b (L is much longer than b). A current I is flowing through the wire. If the radius of the solenoid were doubled (becoming 2b), and all other quantities remained the same, the magnetic field is same, half, twice as strong?  Need to understand the concept.

A solenoid is wound with 2300 turns per meter. When the current is 4.8 A, what is the magnetic field within the solenoid? Treat the solenoid as though it is infinitely long.

A solenoid has length L, total number of turns N and current I. What happens to the magnitude of the magnetic held (B) inside the solenoid if the number of turns is doubled, with the length and current remaining the same? It becomes four times larger. It becomes one-fourth as large. It is unchanged. O It becomes one-half as large. O It becomes twice as large.

Two coplanar and concentric circular loops of wire carry currents of I, = 5.90 A and I, = 2.30 A in opposite directions as in the figure below. Let r, = 12.0 cm and r, = 8.60 cm. (Assume the positive direction along the axis perpendicular to the faces of the loops is out of the screen (towards you) and assume the positive vertical direction is toward the top of the screen.) (a) What is the magnitude of the net magnetic field (in µT) at the center of the two loops? PT (b) What is the direction of the net magnetic field at the center of the two loops? out of the screen O into the screen O toward the top of the screen O toward the bottom of the screen (c) Let r, remain fixed at 12.0 cm and let r, be a variable. Determine the value ofr, (in cm) such that the net field at the center of the loops is zero. cm