Transformers MMM

In transformer primary coil is connected to

• Ac source

• Dc source

• resistor

• inductor

A transformer is designed to convert voltage from 240 V a.c mains to 12 V, and has 4000 turns on its primary coil. turns on its secondary coil should be

• 100

• 200

• 120

• 480

In transformer changing current in primary coil induces changing magnetic field in

• resistor

• inductor

• both A and B

• secondary coil

A transformer is designed to convert voltage from 240 V a.c mains to 12 V, and has 4000 turns on its primary coil. If it is 100% efficient, and current in secondary coil was 0.4 A then current in primary coil should be

• 0.08 A

• 0.05 A

• 0.02 A

• 0.01 A

If secondary voltage is larger than primary voltage, transformer is called a

• positive transformer

• step-up transformer

• negative transformer

• step-down transformer

Which device is designed to allow a small d.c current to control a large d.c current

• Generator

• Motor

• Relay

• Transformer

• A

• B

• C

• D

• A

• B

• C

• D

• A

• B

• C

• D

Which device uses Slip Rings

• D.C electric Motor

• Relay

• Transformer

• A.C generator