Which is true of a step-down transformer but not a step-up transformer? The core is made of copper and the coils are made of iro

Question

3 years ago

11

Which is true of a step-down transformer but not a step-up transformer? The core is made of copper and the coils are made of iro

n. The core is made of iron and the coils are made of copper. The primary winding has fewer coils than the secondary winding. The primary winding has more coils than the secondary winding.

Physics

2 answers:

Lina20 [59] · Answer 1 · 2022-06-26T21:28:21+03:00

Lina20 [59]3 years ago

6 0

Answer:

D

Explanation:

Agata [3.3K] · Answer 2 · 2022-06-26T19:59:03+03:00

The primary winding has more coils than the secondary winding

Explanation:

A transformer is a device consisting of two coils (called primary and secondary coil) wrapped around a soft iron core. As the primary coil is connected to alternate voltage, a variable magnetic field inside the iron core is produced; the lines of this field cut also the secondary coil, and due to the phenomenon of electromagnetic induction, an e.m.f is produced in the secondary coil (so, an alternate voltage).

The voltages in the two coils are related by the transformer equation:

$\frac{V_1}{V_2}=\frac{N_1}{N_2}$ (1)

where

$V_1$ is the voltage in the primary coil

$V_2$ is the voltage in the secondary coil

$N_1$ is the number of turns in the primary coil

$N_2$ is the number of turns in the secondary coil

In a step-down transformer, the voltage in the secondary coil is lower than the voltage in the primary coil (they are used to decrease the voltage in input), therefore:

$\frac{V_1}{V_2}>1$