a. Consider a uniformly wound solenoid having N turns and length 7. Assume I is much...

  

Transcribed Image Text:

a. Consider a uniformly wound solenoid having N turns and length 7. Assume I is much longer than the radius of thewindings and the core of the solenoid is air. i) Find the inductance of the solenoid. (3 marks). ii) Calculate the inductance of the solenoid if it contains 300 turns, its length is 25.0 cm, and its cross-sectional areais 4.00 cm². (2 marks). iii) Calculate the self-induced emf in the solenoid if the current it carries decreases at the rate of 50.0 A/s. (2 marks). b. A transformer connected to a 120-V (rms) ac line is to supply 13,000 V (rms) for a neon sign. To reduce shock hazard, a fuse is to be inserted in the primary circuit; the fuse is to blow when the rms current in the secondary circuit exceeds 8.50 mA. (i) What is the ratio of secondary to primary turns of the transformer? (ii) What power must be supplied to the transformer when the rms secondary current is 8.50 mA? (iii) What current rating should the fuse in the primary circuit have? (8 marks) c. Show that for an L-R-C series circuit the power factor is equal to R/Z. (2 martks) d. An L-R-C series circuit has phase angle -31.5°. The voltage amplitude of the source is 90.0 V. What is the voltage amplitude across the resistor? (3 marks) a. Consider a uniformly wound solenoid having N turns and length 7. Assume I is much longer than the radius of thewindings and the core of the solenoid is air. i) Find the inductance of the solenoid. (3 marks). ii) Calculate the inductance of the solenoid if it contains 300 turns, its length is 25.0 cm, and its cross-sectional areais 4.00 cm². (2 marks). iii) Calculate the self-induced emf in the solenoid if the current it carries decreases at the rate of 50.0 A/s. (2 marks). b. A transformer connected to a 120-V (rms) ac line is to supply 13,000 V (rms) for a neon sign. To reduce shock hazard, a fuse is to be inserted in the primary circuit; the fuse is to blow when the rms current in the secondary circuit exceeds 8.50 mA. (i) What is the ratio of secondary to primary turns of the transformer? (ii) What power must be supplied to the transformer when the rms secondary current is 8.50 mA? (iii) What current rating should the fuse in the primary circuit have? (8 marks) c. Show that for an L-R-C series circuit the power factor is equal to R/Z. (2 martks) d. An L-R-C series circuit has phase angle -31.5°. The voltage amplitude of the source is 90.0 V. What is the voltage amplitude across the resistor? (3 marks)