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Alternating Current question

2007 · Q118
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Alternating Current question

2007 · Q118

NEETPhysicsAlternating CurrentMCQ+4 / −1
The primary and secondary coils of a transformer have 50 and 1500 turns respectively. If the magnetic flux ϕ\phiϕ linked with the primary coil is given by ϕ\phiϕ = ϕ\phiϕ0 + 4t, where ϕ\phiϕ is webers, t is time in seconds and ϕ\phiϕ0 is a constant, the output voltage across the secondary coil is
  1. A
    120 volt
  2. B
    220 volts
  3. C
    30 volts
  4. D
    90 volts.
View written solutionFree

Correct answer: A

Voltage across the primary,

Vp = dϕdt=ddt(ϕ0+4t)={{d\phi } \over {dt}} = {d \over {dt}}\left( {{\phi _0} + 4t} \right) = dtdϕ​=dtd​(ϕ0​+4t)= 4 volt

Also VsVp=NsNp{{{V_s}} \over {{V_p}}} = {{{N_s}} \over {{N_p}}}Vp​Vs​​=Np​Ns​​

Where, Ns = No. of turns across primary coil = 50

Np = No. of turns across secondary coil = 1500

∴\therefore∴ Vs = 150050×4{{1500} \over {50}} \times 4501500​×4 = 120 V

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