Font size
WorksheetsTransformers Quiz
Total questions: 15
Worksheet time: 3hrs 30mins
Transformer is device that
converts AC voltage to current
converts electrical energy to kinetic energy
converts AC voltage to a different level at the same amplitude
converts AC voltage to a different level at the same frequency
Primary loop is connected to the supply while secondary loop is connected to the load.
True
False
Step-up transformer is a transformer that increases:
voltage.
current.
resistance.
conductance.
A secondary coil of a transformer has 500 windings. It was supplied with 200 V. How many windings needed at primary coil to produce 100 V.
(a)
Efficiency of a transformer is:
(output current)/(input current) x100%
(output voltage)/(input voltage) x100%
(output loss)/(input loss) x100%
(output power)/(input power) x100%
A transformer has an output power of 500W. It also has core losses and copper loss of 10W. Determine the efficiency (%) of the transformer.
(a)
Choose the correct statement:
The ratio of the secondary voltage to the primary voltage is equal to the ratio of the primary turn to the secondary turn
The ratio of the primary current to the secondary current is equal to the ratio of the primary voltage to the secondary voltage
The ratio of the primary apparent power to the secondary apparent power is equal to the ration of the primary voltage to the secondary voltage
The ratio of the secondary current to the primary current is equal to the ratio of the primary turn to the secondary turn
Assume primary has 240 turns and secondary has 60 turns. Primary is connected with 120V AC power supply. What is the voltage on the secondary?
30 V
0.333 V
2 V
120V
Laminated insulation are normally used in the transformer:
To reduce the hysteresis effect
To increase the hysteresis effect
To reduce the effect of eddy current
To increase the effect of eddy current
Which type of transformer is used by a power station to transport electricity to cities?
Step Down
Step Up
Either of the two types
Neither of the two types
The ratio of potential difference across the primary coil to the potential difference across the secondary coil of a transformer is 2:1. The primary coil has 20 turns. How many does the secondary coil have?
(a)
A step-up transformer is supplied with 100 V from a DC supply. What will the output voltage be?
(a)
A step-down transformer has an input current of 50 A. The output voltage will be:
less than 50 A
50 A
greater than 50 A
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
A transformer has 100 turns in the primary coil and 25 turns in the secondary coil. When a 120 V is applied to the primary coil, what is the voltage in the secondary coil?
480V
30V
20V
450V
