Blog

Cologne Co. uses a job order cost system. The following entries appeared in Cologne’s work-in-process control account for the month of May:                     Work In Process Inventory (Control) Transactions Debits Credits 5/1  Balance              2,400 5/30 Direct Materials 12,000 5/30 Direct Labor 8,000 5/30 Mfg. Overhead 4,000 5/30 To Finished Goods 23,000      Ending Balance 3,400 Cologne applies manufacturing overhead to production as a percentage of the jobs’ direct labor cost. Job #4711, the only job still in process on April 30th, has been charged with direct labor of $1,000. What was the amount of direct materials charged to Job #4711?

Self-inductance: What is the self-inductance of a solenoid 30.0 cm long having 100 turns of wire and a cross-sectional area of 1.00 × 10-4 m2? (µ0 = 4π × 10-7 T · m/A)

Circular motion of charges: A proton is first accelerated from rest through a potential difference V and then enters a uniform 0.550-T magnetic field oriented perpendicular to its path. In this field, the proton follows a circular arc having a radius of curvature of 2.57 cm. What was the potential difference V? (mproton = 1.67 × 10-27 kg, e = 1.60 × 10-19 C)

Flux: A circular loop of radius 0.20 m is rotating in a uniform external magnetic field of 0.30 T.  Find the magnetic flux through the loop due to the external field when the plane of the loop and the magnetic field vector are(a) parallel. (2.5 points)(b) perpendicular. (2.5 points)(c) at an angle of 30° with each other. (2.5 points)

Cyclotron frequency: Alpha particles (charge = +2e, mass = 6.68 × 10-27 kg, e = 1.60 × 10-19 C) are accelerated in a cyclotron to a final orbit radius of 0.90 m. The magnetic field in the cyclotron is 0.30 T. The period of the circular motion of the alpha particles is closest to

Solenoids: A solenoid having N turns and carrying a current of 2.000 A has a length of 34.00 cm. If the magnitude of the magnetic field generated at the center of the solenoid is  9.000 mT, what is the value of N? (μ0 = 4π × 10-7 T · m/A) 

Cyclotron frequency: An electron enters a magnetic field of 0.75 T with a velocity perpendicular to the direction of the field. At what frequency does the electron traverse a circular path? (mel = 9.11 × 10-31 kg. e = 1.60 × 10-19 C)

LRC series circuits: A series LRC circuit has a sinusoidal voltage supplied to it at 197 kHz with a peak voltage of 270 V a 41-kΩ resistance, a 14-mF capacitor, and a 63-H inductance. What is the peak current for this circuit?

LRC series circuits: A 120-V rms voltage at 1000 Hz is applied to an inductor, a 2.00-µF capacitor and a 100-Ω resistor, all in series. If the rms value of the current in this circuit is 0.680 A, what is the inductance of the inductor?

Motional emf: A 50-cm wire placed in an east-west direction is moved horizontally to the north with a speed of 2.0 m/s.  The horizontal component of the earth’s magnetic field at that location is 25 µT toward the north and the vertical component is 50ìT downward. What is the emf induced between the ends of the wire?