If a transformer doubles its input voltage, what is the current in the secondary coil if the primary coil is 10 A.

20Amp

Explanation:

Using the transformer formula

Vs/Vp = Ns/Np = Ip/Is

Vs/Vp = Ip/Is

Vp is the primary voltage = input voltage

Vs is the secondary voltage = output voltage

Ip is the current in the primary coil

Is is the amount of current in the secondary coil.

If the transformer doubles its input voltage Vp, its output voltage Vs will be

decreased by 2 but the output current will be doubled

Given the input current Ip = 10A, the current in the secondary coil (output current) will be doubled i.e Is = 2(10) = 20A

ok

explanation:

the total distance that martina travels that day is

(distance from home to mom's office) plus (distance from mom's office to school)

plus (distance from school to library) plus (distance from library to friend's house)

plus (distance from friend's house to martina's house).

(we don't know what any of these distance actually is.)