Question

A potentio waire of length 1m has a resistance of 10ohm it is connected in a series with the resistance and a battery of emf 2 volt and of negligible.A source of 10 mV is balanced against length of 40cm of the potentiometer wire .what is the value of external resistance​

Answer 1

Answer:

please give me braniest

Answer 2

Answer:

790ohm

Explanation:

Given,

As the source of e.m.f. E

′

=10mV=10×10

−3

V is balanced by a length of 40cm of the potentiometer wire, it follows that 10×10

−3

=J resistance of 40cm of the potentiometer wire.

If I is current through the potentiometer wire then

J=

R+10

E

=

R+10

2

Now resistance of 40cm of the potentiometer wire =

100

10

×40=4Ω

10×10

−3

=

R+10

2

×4

⇒R=790Ω

Hence, resistance is 790Ω

solution