1. Tardigrade
  2. Question
  3. Physics
  4. A transformer is based on the principle of mutual induction. Input is supplied to primary coil and output is taken across the secondary coil of transformers. It is found that Es / Ep=ip / is when there is no energy loss, the efficiency of a transformer is given by η=(P text output /P text input )=(Es is/Ep ip) How much current is drawn by the primary coil of a transformer which steps down 220 V to 44 V to operate a device with an impedance of 880 Ω ?

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Q. A transformer is based on the principle of mutual induction. Input is supplied to primary coil and output is taken across the secondary coil of transformers. It is found that $E_{s} / E_{p}=i_{p} / i_{s}$ when there is no energy loss, the efficiency of a transformer is given by
$\eta=\frac{P_{\text {output }}}{P_{\text {input }}}=\frac{E_{s} i_{s}}{E_{p} i_{p}}$
How much current is drawn by the primary coil of a transformer which steps down $220\, V$ to $44\, V$ to operate a device with an impedance of $880\, \Omega$ ?

Alternating Current

Solution:

Here, $i_{p}=?, E_{p}=220\, V , E_{s}=44\, V , R_{s}=880\, \Omega$
Current in secondary coil, i.e., $i_{s}=\frac{E_{s}}{R_{s}}=\frac{44}{880}=\frac{1}{20} A$
As, $E_{p} i_{p}=E_{s} i_{s}$
Current drawn by primary coil i.e.,
$\therefore i_{p}=\frac{E_{s} i_{s}}{E_{p}}=\frac{44}{220} \times \frac{1}{20}$
$=0.01\, A$