Chapter 25, Problem 59A

(a)

To determine

To calculate:

Turns ratio of transformer

Answer to Problem 59A

Turns ratio the transformer would have is $\frac{2.0}{1.0}$

Explanation of Solution

Given:

  $V_s=120$ V

  $V_p=240$ V

Formula used:

  $\frac{N_p}{N_s}=\frac{V_p}{V_s}$

where,

  $V_s$ = effective potential difference of secondary coil

  $N_p$ = No of turns of primary coil

  $V_p$ = effective potential difference of primary coil

  $N_s$ = No of turns of secondary coil

Calculation:

Turns ratio the transformer would have can be calculated by the ratio,

  $\frac{N_p}{N_s}=\frac{V_p}{V_s}$

Substituting the values in above ratio,

= $\frac{2.0}{1.0}$

That is from 2.0:1.0

Conclusion:

Hence turns ratio the transformer would have is

(b)

To determine

To calculate:

Current drawn by the hair dryer from $240$ V line.

Answer to Problem 59A

Current drawn by the hair dryer from 240V line is $5$ A

Explanation of Solution

Given:

  $I_s=10$ A

  $V_s=120$ V

  $V_p=240$ V

Formula used:

  $V_p{I}_p=V_s{I}_s$

where,

  $V_s$ = effective potential difference of secondary coil

  $N_p$ = No of turns of primary coil

  $V_p$ = effective potential difference of primary coil

  $N_s$ = No of turns of secondary coil

  $I_p$ = current of secondary coil

Calculation:

Current drawn by the hair dryer from 240V line can be given by the formula,

  $V_p{I}_p=V_s{I}_s$

Rearranging the equation ,

  $I_p=\frac{V_s{I}_s}{V_p}$

Substitutitng the values in the above formula,

  $=\frac{(120)(10)}{240}$

  $=5$ A

Conclusion:

Hence current drawn by the hair dryer from 240V line is $=5$ A