Advertisement Remove all ads

A Cell of Emf 'E' and Internal Resistance 'r' is Connected Across a Variable Load Resistor R. Draw the Plots of the Terminal Voltage V Versus (I) R and (Ii) the Current I. - Physics

Answer in Brief

A cell of emf 'E' and internal resistance 'r' is connected across a variable load resistor R. Draw the plots of the terminal voltage V versus (i) R and (ii) the current I.

It is found that when R = 4 Ω, the current is 1 A and when R is increased to 9 Ω, the current reduces to 0.5 A. Find the values of the emf E and internal resistance r.

Advertisement Remove all ads



Plot for V vs. R



When R = 4 Ω and I = 1 A

We know

Terminal voltage, V = E − Ir

So, we have

V = IR = 4 = E − Ir


E − r = 4   ..... (i)

When R' = 9 Ω and I' = 0.5 A

V = IR = 0.5 × 9 = E − 0.5r


E − 0.5r = 4.5   ..... (ii)

Solving (i) and (ii), we get

 r = 1 Ω and E = 5 V

  Is there an error in this question or solution?
Advertisement Remove all ads
Advertisement Remove all ads

Video TutorialsVIEW ALL [1]

Advertisement Remove all ads

View all notifications

      Forgot password?
View in app×