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प्रश्न
State the principle of a transformer.
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उत्तर
It is based on the principle of ‘electromagnetic induction’. The magnitude of induced e.m.f. is given by the formula.
`"No. of turns in primary coil"/"No.of. turns in secondary coil" = "E.m.f. in primary"/"E.m.f in secondary"`
Neglecting power losses
Elective power fed in the primary (input) = Elective power produced in secondary (output)
or Ep × iP = Es × is
`"E"_"p"/"E"_"s" = "i"_"s"/"i"_"p"`
संबंधित प्रश्न
Find the ratio of primary and secondary currents in terms of turn ratio in an ideal transformer.
State the principle of transformer working with the help of a diagram
The input and output voltage of a transformer are 220 V and 44 V respectively. Find: the turns ratio.
An ideal transformer has 100 turns in the primary and 250 turns in the secondary. The peak value of the AC is 28 V. The rms secondary voltage is nearest to ______
State the mathematical relation between a number of turns in the primary coil to a secondary coil in the step-up transformer.
Assertion: A transfonner cannot work on D.C. supply.
Reason: D.C. changes neither in magnitude nor in direction.
A power transmission line feeds input power at 2300 V to a stepdown transformer with its primary windings having 4000 turns. What should be the number of turns in the secondary in order to get output power at 230 V?
For an LCR circuit, the power transferred from the driving source to the driven oscillator is P = I2Z cos φ.
- Here, the power factor cos φ ≥ 0, P ≥ 0.
- The driving force can give no energy to the oscillator (P = 0) in some cases.
- The driving force cannot syphon out (P < 0) the energy out of oscillator.
- The driving force can take away energy out of the oscillator.
1 MW power is to be delivered from a power station to a town 10 km away. One uses a pair of Cu wires of radius 0.5 cm for this purpose. Calculate the fraction of ohmic losses to power transmitted if
- power is transmitted at 220 V. Comment on the feasibility of doing this.
- a step-up transformer is used to boost the voltage to 11000 V, power transmitted, then a step-down transfomer is used to bring voltage to 220 V. (ρCu = 1.7 × 10–8 SI unit)
The large scale transmission of electrical energy over long distances is done with the use of transformers. The voltage output of the generator is stepped-up because of ______.
