Question

please help me
physics
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Answer 1

Answer:

let E be emf of cell and r be internal resistance

E=0.9(2+r). 1st eq

E=0.3(7+r). 2nd eq

from 1st and 2nd

0.9(2+r)=0.3(7+r)

1.8+0.9r=2.1+0.3r

0.6r=0.3

r=0.5 resistor