Question

A wire of resistance 20 Ω is bent to form a closed square. What is the resistance across a
diagonal of the square?

Answer 1

Answer:

If the wire is bent to form a square, then the resistance of the side of the square =

4

20

=5Ω

Across the diagonal, first calculate resistance through the two sides i.e. R

1

=5+5=10Ω

then through the diagonal,

R

2

=

(5

2

+5

2

)

=5×

2

As R

1

and R

2

are paralell to each other

R

1

=

R

1

1

+

R

2

1

R

1

=

10

1

+

5×

2

1

R

1

=

10×

2

(

2

+

2

)

R

1

=

10×

2

2×

2

R

1

=

10

2

R

1

=

5

1

R=5Ω