2. How is this current produced? Give careful explanations.
3. What is the result of Lenz's law as applied to the dynamo?
4. Apply the first two laws of electromagnetic induction to the dynamo.
5. What is the power of a dynamo if it produces 40 amperes of current at 110 volts?
6. How much power must be applied to this dynamo if its efficiency is 90 per cent.?
7. A motor takes 10 amperes of current at 220 volts; what is the power of the current in watts? If this motor has an efficiency of 95 per cent., how many horse-power of mechanical energy can it develop?
8. Explain why reversing the current in the armature of a motor reverses the direction of rotation.
9. Find the cost of running a washing machine using a 1/2-horsepower motor 2 hours if the cost of the electricity is 10 cents a kilowatt hour.
10. A 1/8-horse-power motor is used to run a sewing machine. If used for 3 hours what will be the cost at 11 cents a kilowatt hour?