Question
#4
Pirys 222 EXAM#2 Spring 2015 Covering Unit" Iastructions: Please read each problem and the information carefully as asked for in the problem. If no eorrect anawer is shown give your answer in (0 represent the mumber of points for that peoblem correct wnswer choics, or fill in tha your answer in ( Numbers in the 13 rymbola [411, A parallel plate capacitor has a dielectric strength of 24 KVim. If the t the maximum potentlal difference that enn be applied Answer: (a) 320 kv. (b) 422 kV. (e)340 kv.(d) 34 kv thickness of the dielectric is 22.Smm (e) 756 kV (f) across the capacitor before the dielectric is damaged (6] H2. For the circuit shawn, R.-270 R.-3 s Og2, R-490 and R.-570 . Determine the oqnivalent tesistance between a and b. Answer: (a) 172 2 (b) 1832. (c) 1972 (d) 204 (e) 215 . (0- [20] M3. is. For the circuit shown below, write three loop rule egation, and a useful junction rule equation involving ar. 2,1nd Loop Loo Loop Junctio 5.0 2.00 1.5 v 10] #4. Circle the letters eorresponding to the TRUE statements. (a) Electrie charge can be stored in a capacitor. and a S magnetic pole. charges. (b) If a permanent magnet is cut into 6 pieces, each piece will have both a N (c) The right hand rules that were presented in Monday's lecture apply to both positive and negative (d) Magnetic field lines form closed loops.() The resistivity of a material is temperature dependernt. C4 Use the figure at the right for problems 5 & 6. For the circuit consisting of air filled, parallel plate capacitors, C-8.80 F, C 3.70 640 F, C-9.60 pF and Cs-5.90 pF, connected as shown at the right. Ca Cs [6] #5. Determine the equivalent capacitance between points A and B. Answer: (a) 1.66pF. (b) 2.74 pF. (c) 3.32 pF. (d) 4.52 F. (e) 5.71 F. ( 5 #6 A material of dielectric constant 5.8 is placed so as to completely fill between the plates of capacitor C. The new value of the capacitance of Ca is Answer: (a) 5.70 x 10*F. (b) 13.0x10F. ()21.5 x 10s F. (d) 32.1 x 10°F. (e)453 x 10*F. ( [S] #7. A potential difference of25.0 volts is applied across a branch, A-B, consisting of three 150 mF capacitors that are connected in series, as shown. What charge will be on the middle capacitor C? Answer: (a) 1.25 C. (b) 2.86 C. (c) 3.91 C. (d) 4.66 C. (e) 5.85 C. ( (61 #8. A current of35.4 x 10-6 A exists in a solid cylindrical wire whose diameter is 1.98 mm. Calculate the magnitude of t current density in the wire. Answer: (a) 1.77 A/m. (b) 5.46 A/m2. (c) 8.25 A/m2. (d) 10.1 A/m2. (e) 11.3 A/m. o section of a certain wire (resistivity 1.63 x 10* (Q2.m) at room temperature), has a circular cross section of radius 18.2 x 10'm. Determine the value of its resistance at room temperature. Answer: (a) 1.32 (b) 4.76 . (c) 821. (d) 12.2 , (e) 16.862. (f)
Explanation / Answer
maximum potential difference V = E*d
E = dielectric strength = 24 k V/mm
d = thichness of dielectric = 22.5 mm
maximum potential difference V = 24*22.5 k V
maximum potential difference V = 540 kV
OPTION ( C )
