Question

The electric motor in a toy train requires a voltage of 2.1 V. Find the ratio of turns on the primary coil to tuns on the secondary coll in a translormer that will step the 110 V household voltage down to 2.1 V Express your answer using two significant figures.

Answer 1

Answer:

1100 : 21

Explanation:

Vp = 110 V

Vs = 2.1 V

Let the number of turns in primary coil is Np and the number of turns in secondary coil is Ns.

According to the principle of transformer, when an ideal transformer is there

$\frac{N_{s}}{N_{P}}=\frac{V_{s}}{V_{P}}$

$\frac{N_{s}}{N_{P}}=\frac{2.1}{110}$

$\frac{N_{s}}{N_{P}}=\frac{21}{1100}$

$\frac{N_{p}}{N_{s}}=\frac{1100}{21}$

Thus, the ratio of number of turns to the primary to the secondary is 1100 : 21.