English

A Transformer is Used to Step up an Alternating Emf of 200v to 440v. If the Primary Coil Has 1000 Turns, Calculate the Number of Turns in the Secondary Coil.

Advertisements
Advertisements

Question

A transformer is used to step up an alternating emf of 200V to 440V. If the primary coil has 1000 turns, calculate the number of turns in the secondary coil. 

Answer in Brief
Numerical
Advertisements

Solution

This is an example of step-up transformer

`n_s/n_p = V_s/V_p`

`therefore n_s/1000 = 440/200`

`therefore n_s = 2200  "turns"`

shaalaa.com
  Is there an error in this question or solution?
2018-2019 (March) Set 1

RELATED QUESTIONS

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.


Describe briefly and two energy losses, giving the reasons for their occurrence in actual transformers ?


Why is the core of a transformer made of soft iron?


A 200V/120V step-down transformer of 90% efficiency is connected to an induction stove of resistance 40 Ω. Find the current drawn by the primary of the transformer.


A transformer is essentially an a.c. device. It cannot work on d.c. It changes alternating voltages or currents. It does not affect the frequency of a.c. It is based on the phenomenon of mutual induction. A transformer essentially consists of two coils of insulated copper wire having different numbers of turns and wound on the same soft iron core.

The number of turns in the primary and secondary coils of an ideal transformer is 2000 and 50 respectively. The primary coil is connected to a main supply of 120 V and secondary coil is connected to a bulb of resistance 0.6 Ω.

The value of current in primary coil is ______.


For an LCR circuit, the power transferred from the driving source to the driven oscillator is P = I2Z cos φ.

  1. Here, the power factor cos φ ≥ 0, P ≥ 0.
  2. The driving force can give no energy to the oscillator (P = 0) in some cases.
  3. The driving force cannot syphon out (P < 0) the energy out of oscillator.
  4. The driving force can take away energy out of the oscillator.

A transformer operating at primary voltage 8 kV and secondary voltage 160 V serves a load of 80 kW. Assuming the transformer to be ideal with purely resistive load and working on unity power factor, the loads in the primary and secondary circuit would be:


What type of transformer is used in a mobile phone charger?


What is the induced EMF in the primary coil?


What is the induced EMF in the secondary coil?


Share
Notifications

Englishहिंदीमराठी


      Forgot password?
Use app×