PractiseQuestion bank
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12 questions
SA-5054-EL8-0012 marksL1 FoundationCalculatorTurns ratio
A transformer has 1000 turns on its primary coil and 50 turns on its secondary. The primary voltage is 230 V. Calculate the secondary voltage. Salam Academy Original Practice · Proposed mark scheme
SA-5054-EL8-0031 markL1 FoundationCalculatorTurns ratio
A step-up transformer has
Salam Academy Original Practice · Proposed mark scheme
SA-5054-EL8-0041 markL1 FoundationCalculatorTurns ratio
A transformer will not work with a steady d.c. supply because
Salam Academy Original Practice · Proposed mark scheme
SA-5054-EL8-0061 markL1 FoundationCalculatorTransmission
Electricity is transmitted at very high voltage because
Salam Academy Original Practice · Proposed mark scheme
SA-5054-EL8-0091 markL1 FoundationCalculatorTurns ratio
A step-up transformer has a turns ratio Np:Ns=1:20. The input is 25 kV. Calculate the output in kV. Salam Academy Original Practice · Proposed mark scheme
SA-5054-EL8-0101 markL1 FoundationCalculatorTurns ratio
The core of a transformer is made of
Salam Academy Original Practice · Proposed mark scheme
SA-5054-EL8-0121 markL1 FoundationCalculatorTurns ratio
A transformer works because
Salam Academy Original Practice · Proposed mark scheme
SA-5054-EL8-0022 marksL2 StandardCalculatorTurns ratio
A transformer changes 240 V to 12 V. Its primary has 2000 turns. Calculate the number of turns on the secondary. Salam Academy Original Practice · Proposed mark scheme
SA-5054-EL8-0052 marksL2 StandardCalculatorTransmission
An ideal transformer has a primary current of 0.50 A at 230 V. Its secondary voltage is 23 V. Calculate the secondary current. Salam Academy Original Practice · Proposed mark scheme
SA-5054-EL8-0072 marksL2 StandardCalculatorTransmission
A current of 100 A flows through transmission cables of total resistance 2.0 Ω. Calculate the power lost in the cables, in kW. Salam Academy Original Practice · Proposed mark scheme
SA-5054-EL8-0082 marksL3 ExamCalculatorTransmission
The same power is transmitted at 10 times the voltage. By what factor is the power lost in the cables reduced? Salam Academy Original Practice · Proposed mark scheme
SA-5054-EL8-0113 marksL3 ExamCalculatorTransmission
A power station transmits 1.0 MW at 25 kV through cables of resistance 5.0 Ω. Calculate the percentage of the power lost in the cables. Salam Academy Original Practice · Proposed mark scheme