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प्रश्न
A transformer is designed to work from a 240 V a.c. mains and to give a supply of 8 V to ring a house bell. The primary coil has 4800 turns. How many turns will be in the secondary coil?
A transformer is designed to give a supply of 8 V to ring a house-bell from the 240 V a.c. mains. The primary coil has 4800 turns. How many turns will be in the secondary coil?
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उत्तर
Input ac voltage Vp = 240 V.
Number of turns in primary coil Np = 4800
No. of turns in secondary coil Ns = ?
Output voltage Vs = 8 V.
We know that
`"V"_"p"/"V"_"s" = "N"_"p"/"N"_"s"`
`"N"_"s" = ("N"_"p" xx "V"_"s")/ "V"_"p"`
= `(4800 xx 8) / 240`
= 160
The number of turns in the secondary coil is 160.
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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.
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