Advertisements
Advertisements
प्रश्न
The power supply to the primary coil of a transformer is 200 W. Find
(i) Current in primary coil if the e.m.f. supply to it is equal to 220V.
(ii) The number of turns in the primary coil is equal to 80 and that in secondary is 800. What is the transformation ratio?
(iii) Name the type of transformer.
(iv) What will be the output voltage?
(v) What is the current in the secondary coil for an ideal transformer?
(vi) What is the output power?
(vii) Is output and input power equal?
(viii) Compare the current flowing in a secondary coil and in a primary coil.
Advertisements
उत्तर
(i) P(Power) = 200W = VI = Ep × Ip
∴ P = 200 = 200 × Ip
∴ Current in the primary coil = `200/220`
Ip = 0.909 A
(ii)
Transformation ratio `"E"_"s"/"E"_"p" = "N"_"s"/"N"_"p" = 800/80 = 10`
(iii) It is a step up transformer.
(iv) Using `"E"_"s"/"E"_"p" = "N"_"s"/"N"_"p" = 10`
` therefore "E"_"s"/200 = 10`
∴ Es = 2200 V
(v) Using Ep × Ip = 2200 × Is
∴ 200 = 2200 × Is
∴ Is = `2/22 = 0.090` A
(vi) Outpput power = Es × Is = `(2200 xx 0.0909)/100 = 200`W
(vii) Yes, It is equal, because it is an ideal transformer, for an ideal transformer
Efficiency = η = `"Outout power"/"Input power" = 1 "or" 100%`
i.e., there is no energy loss due to any cause.
(viii) Is = 0.0909 A and Ip = 0.909 A
Less current flows through the secondary coil than in the primary coil because it is a step-up transformer.
संबंधित प्रश्न
Draw a labeled diagram of a step-down transformer.
Derive an expression for e.m.f. and current in terms of turns ratio
What is a transformer? On what principle does it work?
Copy the given diagram of a transformer and complete it. Name the parts A and B. Name the part you have drawn to complete the diagram. What is the material of this part? Is this transformer a step-up or step-down? Give reason.
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 ______
The primary of a transformer has 40 turns and works on 100 V and 100 W. Find a number of turns in the secondary to step up the voltage to 400 V. Also calculate the current in the secondary and primary.
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.
A 60 W load is connected to the secondary of a transformer whose primary draws line voltage. If a current of 0.54 A flows in the load, what is the current in the primary coil? Comment on the type of transformer being used.
What is a transformer?
A step down transformer connected to an ac mains supply of 220 V is made to operate at 11 V, 44 W lamp. Ignoring power losses in the transformer, what is the current in the primary circuit?
