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प्रश्न
What are step-up and step-down transformers?
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उत्तर
- A transformer that increases the voltage by decreasing current is known as a step-up transformer.
- A transformer that decreases the voltage by increasing the current is a step-down transformer.
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संबंधित प्रश्न
Derive an expression for e.m.f. and current in terms of turns ratio
What is the function of a transformer in an a.c. circuit? How do the input and output powers in a transformer compare?
State the principle of a step-up transformer. Explain, with the help of a labeled diagram, its working ?
Describe the construction and working of a transformer with a neat labelled diagram.
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?
The line that draws power supply to your house from street has ______.
- zero average current.
- 220 V average voltage.
- voltage and current out of phase by 90°.
- voltage and current possibly differing in phase `phi` such that `|phi| < pi/2`.
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 self-inductance of a closely wound coil of 200 turns is 10 mH. Determine the value of magnetic flux through the cross-section of the coil when the current passing through the coil is 4 mA.
Derive the equation for a transformer.
