Magnetic field lines occur.. Around a wire which does not have current.
Around a current carrying wire.
In a wire
Vertical through the wire

An ideal transformer has 60 turns in its primary coil and 360 turns in its secondary coil. if the input rms voltage for the 60-turn coil is 120 v, what is the output rms voltage of the secondary coil?

Athin, square metal plate measures 14 cm on each side and has emissivity of 0.60. the plate is heated to a temperature of 745°c. what is the rate at which the plate radiates energy ? the stefan-boltzmann constant is 5.67 × 10-8 w/(m2 ? k4). remember that the plate will radiate energy from both its top and bottom surfaces.

Which is not a characteristic of a heat pump? a. it is used in air conditioners. b. it uses a refrigerant. c. it requires no work. d. it reverses the normal flow of thermal energy.