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प्रश्न
The primary coil of an ideal step-up transformer has 100 turns and the transformation ratio is also 100. The input voltage and power are 220 V and 1100 W, respectively. Calculate the
(a) number of turns in secondary
(b) current in the primary
(c) a voltage across secondary
(d) current in secondary
(e) power in secondary
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उत्तर
(a) Number of turns in secondary coil is given by
`N_S/N_P=n`
`=>N_S/100=100`
⇒NS=10,000
(b) Current in primary is given by
IPVP=P
`=>I_P=1100/220=5A`
(c) Voltage across secondary is given by
`V_S/V_P=N_S/N_P=n`
⇒VS=100×220=22,000 V
(d) Current in secondary is given by
VSIS=P
`=>I_S=P/V_S=1100/22000=0.05A`
(e) Power in secondary is power in primary in an ideal transformer.
= 1,100 W
संबंधित प्रश्न
The teachers of Geeta’s school took the students on a study trip to a power generating station, located nearly 200 km away from the city. The teacher explained that electrical energy is transmitted over such a long distance to their city, in the form of alternating current (ac) raised to a high voltage. At the receiving end in the city, the voltage is reduced to operate the devices. As a result, the power loss is reduced. Geeta listened to the teacher and asked questions about how the ac is converted to a higher or lower voltage.
1) Name the device used to change the alternating voltage to a higher or lower value. State one cause for power dissipation in this device.
2) Explain with an example, how power loss is reduced if the energy is transmitted over long distances as an alternating current rather than a direct current.
3) Write two values each shown by the teachers and Geeta.
Name two kind of energy loss in a transformer. How is it minimized?
Describe briefly and two energy losses, giving the reasons for their occurrence in actual transformers ?
Draw a labelled diagram to show the various parts of a step-up transformer and step down transformer.
A transformer lowers e.m.f. 220 V to 12 volts. If the number of turns in primary are 8800, how many turns are in secondary coil?
The primary and secondary coils of a transformer each have an inductance of 200 x 10-6 H. The mutual inductance between the windings is 4 x 10-6 H. What percentage of the flux from one coil reaches the other?
Distinguish between Step up and Step Down Transformer.
The primary winding of a transformer has 100 turns and its secondary winding has 200 turns. The primary is connected to an a.c supply of 120 V and the current flowing in its is 10 A. The voltage and the current in the secondary are ______.
