Which circuit-a or b-represents a series circuit? explain your answer.

Circuit-A is a series circuit.  There's only one road that electrons can take to get from one battery terminal to the other one.  There's no point in the circuit where an electron has to decide which path to take.

Circuit-B is a parallel circuit.  At each of the two 'dimples' across the top, an electron has a choice:  It can turn right and go through a bulb, OR keep going straight on to the NEXT bulb.

Circuit-C is a series circuit.  There's only one road that electrons can take to get from one battery terminal to the other one.  There's no point in the circuit where an electron has to decide which path to take.

Circuit-D is called a "series-parallel circuit", because it has characteristics of both kinds.  Devices #2 and #3 are in parallel, but Device #1 is in series with them.

Circuit-E is a parallel circuit.  There are two places across the top where an electron has a choice:  It can decide to take a right turn and go through the bulb OR keep going straight on to the next bulb.  

a solenoid is created by wrapping a l = 90 m long wire around a hollow tube of diameter d = 4.5 cm.   the wire diameter is d = 0.9 mm.   the solenoid wire is then connected to a power supply so that a current of i = 9 a flows through the wire.

randomized variablesl = 90 m

d = 4.5 cm

d = 0.9 mm

i = 9 a                                          

write an expression for the number of turns, n, in the solenoid. you do not need to take into account the diameter of the wire in this calculation.

calculate the number of turns, n, in the solenoid.

write an expression for the length of the solenoid (l2) in terms of the diameter of the hollow tube d.

calculate the length of the solenoid (l2)   in meters.

calculate the magnitude of the magnetic field at the center of the solenoid in teslas.

explanation:

b.a device that inputs heat into a cool object