Item 12 Electricity is distributed from electrical substations to neighborhoods

Question

Item 12 Electricity is distributed from electrical substations to neighborhoods at 1.4x10^4V This is a 60Hz Express your answer using two significant figures. oscillating (AC) voltage. Neighborhood transformers, seen on utility poles, step this voltage down to the 120V that is delivered to your house. Part A How many turns does the primary coil on the transformer have if the secondary coil has 120 turns? nprim=1.4 x 10^4 turns Part B No energy is lost in an ideal transformer, so the output power Pout from the secondary coil equals the input power P to the primary coil. Suppose a neighborhood transformer delivers 290A at 120 V. What is the current in the 1,4x10^4V line from the substation? Express your answer using two significant figures. Ii= 33833 A Submit My Answers Give Up Incorrect; Try Again; 5 attempts remaining I'm having trouble getting the right value for the second part of the question.

Explanation / Answer

B)

Input power = output power

V1*I1 = V2*I2

I1 = I2*(V2/V1)

= 290*(120/(1.4*10^4))

= 2.486 A

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