Physics crossword 2

Across

• 1. an e.m.f. generated by a spinning motor that opposes the p.d. driving the motor and limits the speed of the motor (4, 3)
• 5. the ratio of turns in the primary and secondary coils of a transformer (5, 5)
• 6. the product of current I and number of turns N in a solenoid I x N (7, 5)
• 7. a thermal energy transfer resulting in an increase in internal energy, often of the surroundings (11)