Bright Tutorials Bright Tutorials
ICSE Class 10 Physics Question 15 of 20

Electro-magnetism — Question 4

Back to all questions
4
Question

Question 4

The input and output voltages of a transformer are 220 V and 44 V respectively. Find (a) the turns ratio (b) the current in input circuit if the output current is 2 A.

Answer

(a) Given,

Ep = 220 V

ES = 44 V

Now,

EsEp=NsNp\dfrac{E_s}{E_p} = \dfrac{N_s}{N_p}

Substituting the values in the formula we get,

44220=NsNp⇒NsNp=44220⇒NsNp=15\dfrac{44}{220} = \dfrac{N_s}{N_p} \\[0.5em] \Rightarrow \dfrac{N_s}{N_p} = \dfrac{44}{220} \\[0.5em] \Rightarrow \dfrac{N_s}{N_p} = \dfrac{1}{5} \\[0.5em]

Hence, turns ratio = 1 : 5

(b) Is = 2 A

Ip = ?

From relation,

EsIs=EpIp{E_s}{I_s} = {E_p}{I_p}

Substituting the values in the formula we get,

44×2=220×Ip⇒Ip=44×2220⇒Ip=0.4A44 \times 2 = 220 \times I_p \\[0.5em] \Rightarrow I_p = \dfrac{44 \times 2}{220} \\[0.5em] \Rightarrow I_p = 0.4 A \\[0.5em]

Hence, input current = 0.4 A