Question

A cell of emf (E) and internal resistance r is connected across a variable
external resistance R. The graph of terminal potential difference V as a
function of R is ?

I have attached the graphs too pls tell me which one is the answer ?​

Answer 1

Answer:

Heyy mate ...

Here is your answer

Explanation:

yesterday I aslo given exam so I tick the option c

But I search it on google then there is correct option is (B)

Hope it's help you.

Answer 2

Answer:

Explanation:

Here the terminal voltage , V=E−ir...(1) and the current i=E/(R+r)

Now, V=E−  

(R+r)

E

​  

r=  

R+r

ER

​  

=  

(1+r/R)

E

​  

=...(2)

According to equation (1) and (2), the graph V vs i and V vs R will be as shown in figure.

As i=E/(R+r) so 1=E/(4+r) or E=4+r...(3) and

0.5=E/(9+r) or 2E=9+r....(4)

using (3), 2(4+r)=9+r or r=1Ω

Thus, E=4+1=5V

solution