Advertisements
Advertisements
प्रश्न
Find the ratio of primary and secondary currents in terms of turn ratio in an ideal transformer.
Advertisements
उत्तर
According to law of conservation of energy,
Input electrical power = Output electrical power
EpIp = EsIs
`:.E_s/E_p=I_p/I_s`
`I_p/I_s=E_s/E_p=N_s/N_p`
`=>I_p/I_s=n`
APPEARS IN
संबंधित प्रश्न
Express the turn ratio in terms of voltages.
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.
State two ways through which the strength of an electromagnet can be increased.
What is the function of a transformer in an a.c. circuit? How do the input and output powers in a transformer compare?
Describe briefly and two energy losses, giving the reasons for their occurrence in actual transformers ?
Draw a labeled diagram of a full wave rectifier circuit. State its working principle. Show the input-output waveforms ?
Read the following paragraph and answer the question:
Long distance power transmissions
The large-scale transmission and distribution of electrical energy over long distances is done with the use of transformers. The voltage output of the generator is stepped up. It is then transmitted over long distances to an area sub-station near the consumers. There the voltage is stepped down. It is further stepped down at distributing sub-stations and utility poles before a power supply of 240 V reaches our homes.
Which of the following statement is true?
In a transformer, number of turns in the primary coil are 140 and that in the secondary coil are 280. If current in primary coil is 4 A, then that in the secondary coil is ______.
What is a transformer?
What type of transformer is used in a mobile phone charger?
