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प्रश्न
A step-down transformer connected to the main supply of 220 V is used to operate 11V,88W lamp. Calculate
- Voltage transformation ratio and
- Current in the primary
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उत्तर
Given data:
Vp = 220 V, Ps = 88 W, Vs = 11 V
Transformation ratio K = `"V"_"s"/"V"_"p"`
K = `11/220 = 1/20 = 1 : 20 = 1/20`
Current in the primary Ip = ?
`"P"_"S" = "V"_"S" "I"_"S"`
`"I"_"S" = "P"_"S"/"V"_"S" = 88/11` = 8 A
`therefore "I"_"p"/"I"_"S" = "K"`
`"I"_"p" = "KI"_"S"`
`therefore "I"_"p" = 1/20 xx 8 = 2/5 = 0.4`
Ip = 0.4 A
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संबंधित प्रश्न
A group of students while coming from the school noticed a box marked "Danger H.T. 2200 V" at a substation in the main street. They did not understand the utility of a such a high voltage, while they argued, the supply was only 220 V. They asked their teacher this question the next day. The teacher thought it to be an important question and therefore explained to the whole class.
Answer the following questions:
(i) What device is used to bring the high voltage down to low voltage of a.c. current and what is the principle of its working ?
(ii) Is it possible to use this device for bringing down the high dc voltage to the low voltage? Explain
(iii) Write the values displayed by the students and the teacher.
Mention various energy losses in transformer device
Why is the core of a transformer laminated?
Explain why an induced current must flow in such a direction so as to oppose the change producing it.
The secondary windings of a transformer in which the voltage is stepped down are usually made of thicker wire than the primary. Explain why.
Applying e.m. f to primary coil is 210 V. If the number of turns in primary coil is 200 turns and that of in secondary coil is 20 turns, then find out the output voltage. Name the type of transformer.
A transformer lowers e.m.f. from 220 V to 15 V. If the number of turns in primary are 3520, how many turns are in the secondary coil?
Mention the various energy losses in 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?
What type of transformer is used in a mobile phone charger?
