Question

A cell In a deaf aid supplies a current of 25.0 mA through a resistance of 400w when the wearer turns up the volume,the resistance is changed to 100w and the current rises to 60mA what is the emf and internal resistance of the cell

Answer 1

Step-by-step explanation:

See drawing

Using V= I * resistance

v = (.025 A) * (r+400 Ω) <====given

and

v = (.060A) * ( r+100 Ω)

equate the two equations

.025(r + 400) = .060(r+100) <==== solve for r = 114 .3 Ω

then use this value in either of the equations to calculate v = 12.9 v