Transformers,poly phase generator

If a transformer reduces voltage, it is called a....................... transformer.

• step left

• step right

• step up

• step down

If a transformer increases voltage, it is called a ......... transformer.

• step right

• step left

• step up

• step down

The winding of wire around a core which is connected to a source of energy is called the ....... coil.

• primary

• secondary

• tertiary

Calculate potential difference in the secondary coil based on the information given below.

Vp = 240 V

Np = 20

Ns = 125

Vs ?

• 1500

• 500

• 1000

• 2000

Why transformers work with A.C. current but not D.C.

• A.C current produces changing magnetic field.

• D.C current produces changing magnetic field.

• D.C current is weak

• A.C current is powerful

What is the material used for construction of transformer core?

• Aluminium

• Copper

• Iron

• Wood

This picture is an example of a ________________.

• Motor

• Generator

• Step-up transformer

• Step-down transformer

If the transformer shown is 80% efficient, calculate the power at the primary coil.

• 30W

• 24W

• 36.5W

• 19.2W

What is the function of the generator?

• Convert electrical energy to mechanical (kinetic) energy

• Convert electrical energy to thermal energy (heat)

• Convert mechanical (kinetic) energy to electrical energy

What is the function of the transformer?

• Convert electrical energy to mechanical (kinetic) energy

• Convert electrical energy to thermal energy (heat)

• Convert mechanical (kinetic) energy to electrical energy

• Step up or step down the voltage