The voltage and current in the primary of a transformer are 200V and 2Arespectively. lf the transformer is used to light ten 12 V, 30 W bulbs, calculate its...
Question 1 Report
The voltage and current in the primary of a transformer are 200V and 2Arespectively. lf the transformer is used to light ten 12 V, 30 W bulbs, calculate its efficiency.
Answer Details
The efficiency of a transformer is given by the ratio of the output power to the input power. In this case, the input power is given by the product of the voltage and current in the primary coil of the transformer:
Input power = Voltage × Current = 200V × 2A = 400W
The output power is given by the total power of the bulbs, which is the product of their voltage and current ratings, multiplied by the number of bulbs:
Output power = Number of bulbs × Voltage × Current = 10 × 12V × 2.5A = 300W
The efficiency of the transformer is therefore:
Efficiency = Output power / Input power = 300W / 400W = 0.75 or 75%
Therefore, the correct option is (c) 75%.
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