برقی مقناطیسیت

A current carrying wire is surrounded by:

• 1 A gravitational field only
• 2 A magnetic field
• 3 Nothing
• 4 A sound field

A device that converts mechanical energy into electrical energy is a:

• 1 Battery
• 2 Transformer
• 3 Motor
• 4 Generator

A transformer works on the principle of:

• 1 Reflection
• 2 Mutual induction
• 3 Friction
• 4 Refraction

A step up transformer has:

• 1 More turns in the primary
• 2 More turns in the secondary
• 3 No core
• 4 Equal turns

A transformer has 100 primary turns, 500 secondary turns and a 20 V input. What is the output voltage?

• 1 100 V
• 2 20 V
• 3 500 V
• 4 4 V