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A step-down transformer reduces the voltage of a transmission line from $200 V$ to $220 V$ . The power delivered by it is $880 W$ and its efficiency is $88 %$ . The input current is

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Important Questions on Physics

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General Science>General Science>Physics>Magnetism

A transformer is used to light a

100 W,

110 V

lamp from a

220 V

supply. If the supply current is

0.6 A,

the efficiency of the transformer is

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General Science>General Science>Physics>Magnetism

An ideal transformer has $500$ and $5000$ turn in primary and secondary windings, respectively. If the primary voltage is connected to a $6 V$ DC battery, then the secondary voltage is:

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General Science>General Science>Physics>Magnetism

Which of the following remain constant in a transformer ?

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General Science>General Science>Physics>Magnetism

A transformer has efficiency

80 %

. It works at

5 kW

and

150 V

. If the secondary voltage is

240 V

, the secondary current is

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General Science>General Science>Physics>Magnetism

A power transmission line feeds input power at

2300 V

to a step down transformer with its primary windings having

4000

turns. The output power is delivered at

230 V

by the transformer. If the current in the primary of the transformer is

5 A

and its efficiency is

90 %

, the output current would be:

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General Science>General Science>Physics>Magnetism

For the given circuit, comment on the type of transformer used :

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General Science>General Science>Physics>Magnetism

A step-up transformer operates on a

230 V

line and a load current of

2 A

. The ratio of primary and secondary windings is

1 : 25

. Then the current in the primary is

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General Science>General Science>Physics>Magnetism

A transformer is used to glow a

140 W - 240 V

bulb at

240 V

AC. If current in the primary coil is

0.7 A

, then the efficiency of the transformer is

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General Science>General Science>Physics>Magnetism

A transformer having efficiency of

90 %

is working on

200 V

and

3 k W

power supply. If the current in the secondary coil is

6 A

the voltage across the secondary coil and the current in the primary coil respectively are:

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General Science>General Science>Physics>Magnetism

A transformer operates at

V_{p} = 6 kV

on the primary side and supplies electric energy at

V_{S} = 220 V

to a number of houses in a town. If the total power consumption of the town is

7.2 kW

, the current (in amperes) in the primary is

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General Science>General Science>Physics>Magnetism

A primary coil is connected with an

A C

source and a bulb is connected with the secondary coil. The voltage across the bulb is

6.0 V

and the current through the bulb is

0.4 A

, The turns ratio is

5 : 1 (Np : Ns = 5 : 1)

. Calculate the current in the primary coil.

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General Science>General Science>Physics>Magnetism

A power transmission line feeds input power at

2300 V

to a step-down transformer with its primary windings having

4000

turns giving the output power at

230 V

. If the current in the primary coil of the transformer is

5 A

and its efficiency is

90 %

, the output current would be:

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General Science>General Science>Physics>Magnetism

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?

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General Science>General Science>Physics>Magnetism

A step-down transformer has turn ratio

20 : 1

. If

8 V

is applied across

0.4 Ω

secondary then the primary current will be

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General Science>General Science>Physics>Magnetism

How much current is drawn by the primary coil of a transformer, which steps down

220 V

55 V

to operate a device with an impedance of

275 Ω ?

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General Science>General Science>Physics>Magnetism

A step-up transformer operates on a

230 V

line and supplies current of

2 A

to a load. The ratio of the primary and secondary windings is

1 : 25

. The current in the primary coil is

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General Science>General Science>Physics>Magnetism

A transformer is employed to

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General Science>General Science>Physics>Magnetism

A current of

6 A

is flowing at

220 V

in the primary coil of a transformer. If the voltage produced in the secondary coil is

1100 V

and

40 %

of power is lost, then the current in the secondary coil will be:

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General Science>General Science>Physics>Magnetism

A transformer consisting of

300

turns in the primary and

150

turns in the secondary gives output power of

2.2 k W

. If the current in the secondary coil is

10 A

, then the input voltage and current in the primary coil are:

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General Science>General Science>Physics>Magnetism

A transformer of efficiency

90 %

has turns ratio

10 : 1 .

If the voltage across the primary is

220 V

and current in the primary is

0.5 A,

then the current in secondary is

A step-down transformer reduces the voltage of a transmission line from 200 V to 220 V. The power delivered by it is 880 W and its efficiency is 88 %. The input current is

Important Questions on Physics

Learn and Prepare for any exam you want !

A step-down transformer reduces the voltage of a transmission line from $200 V$ to $220 V$ . The power delivered by it is $880 W$ and its efficiency is $88 %$ . The input current is