Question

72.
are used in series correctly, the balancing length obtained is 400 cm. When they are used in
series but E, is connected with reverse polarities, the balancing length obtained is 200 cm. Ratio
of emf of cells is
Two cells of emf E, and E, are to be compared in a potentiometer (E, > E). When the cells​

Answer 1

Physics

5 points

Answer:

Answer

4

4.0

E₁:E₂ = 3:1

Explanation:

When the cells are connected initially, in series such that their voltages add up, corresponding length= 400cm

In Potentiometer, Voltage across the the wire is given by V=k(L)

  This is because

  V=i(R)

=K(L) [∵ wires of potentiometer has same cross-sectional area]

  V=i(ρ)

$(\frac{L}{A})$

first case

So when they are connected in

$\boxed{E1+E2 =K(400)} ---(1)$

,

And in

second case

,  

$\boxed{E1-E2 =K(200)} ---(2)$

⇒

$\frac{(1)}{(2)}$

$\frac{E1+E2}{E1-E2} = 2$

⇒ E₁ = 3E₂

  V=i(R)

  V=i(ρ)

$(\frac{L}{A})$

Physics

5 points

,

⇒

$\frac{(1)}{(2)}$

$\frac{E1+E2}{E1-E2} = 2$

⇒ E₁ = 3E₂

$\boxed{\frac{E1}{E2} =\frac{3}{1}}$

∴  

Hope this answer helped you :)