Reference no: EM13898877
1. The primary coil of a step-up transformer draws 100 W. How much power is provided by the secondary coil?
2. An ideal transformer has 50 turns in its primary and 250 turns in its secondary. 12 V ac is connected to the primary.
a. Find the volts ac available at the secondary.
b. Show that a 10-Ω device connected to the secondary draws a current of 6 A.
c. How much power is supplied to the primary?
3. A model electric train requires 6 V to operate. If the primary coil of its transformer has 240 windings, how many windings should the secondary have if the primary is connected CO a 120-V household circuit?
4. Neon signs require about 12,000 V for their operation. What should be the ratio of the number of loops in the secondary to the number of loops in the primary for a neon-sign transformer that operates from 120-V lines?
5. 100 kW (105 W) of power is delivered to the other side of a city by a pair of power lines between which the voltage is 12,000 V.
a. How much current is carried in the lines?
b. Each of the two lines has a resistance of 10 Ω. What is the voltage difference between the two ends of each line? (Think carefully. This voltage is not that between the two lines.)
c. What power is wasted as heat in both lines together (distinct from power delivered to customers)?
How does this compare with the power being delivered?