Question

two coils are connected in series in one gap of a metre bridge and the null point is obtained in the middle of the wire by putting a resistance of 75 ohms in the other app the two coils are then connected in parallel and the null point is obtained in the middle of the wire by connecting a resistance of 18 ohms in the other find the resistance of each coil
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Answer 1

Explanation:

⇒R

1

:R

2

:R

3

=

A

1

L

1

:

A

2

L

2

:

A

3

L

3

=

A

1

1

:

2A

1

L

2

:

2

A

1

L

3

=1:

2

2

:

2

1

3

R

1

:R

2

:R

3

=1:1:6

As they are in parallel Iα

R

1

⇒I

1

:I

2

:I

3

=

R

1

1

:

R

2

1

:

R

3

1

=1:1:

6

1

=6:6:1

Power=VI⇒PαI

⇒P

1

:P

2

:P

3

=I

1

:I

2

:I

3

=6:6:1