Question

21
A potentiometer having a wire 3 m long is connected to the primary circuit containing a battery of 3 volt.
A Leclanche cell gives a null point at 145 cm and a Daniel cell at a point 110cm. The ratio of e.mf.s of
the two cells is
lal
a) 29:22
b) 30 : 37
c) 45 : 67
d) 45: 76​

Answer 1

Answer:

Given: E

1

=ρl

1

E

1

+E

2

=ρl

2

Formula used for solution

E

2

E

1

=

l

2

l

1

E

1

E

1

+E

2

=

ρl

1

ρl

2

=

l

1

l

2

1+

E

1

E

2

=

l

1

l

2

E

1

E

2

=

l

1

l

2

−1=

l

1

l

2

−l

1

∴

E

2

E

1

=

l

2

−l

1

l

1

=

480−280

280

=

200

280

E

1

:E

2

=7:5