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A battery of e.m.f 3.0V is connected across a potentiomet...

A battery of e.m.f 3.0V is connected across a potentiometer wire AB of length 10\(\Omega m^{-1}\) as illustrated in the diagram above. If the jockey J makes contact at the 30cm mark, determine the resistance of length AJ and voltage across AJ.

A battery of e.m.f 3.0V is connected across a potentiometer wire AB of length 10Ωm1 as illustrated in the diagram above. If the jockey J makes contact at the 30cm mark, determine the resistance of length AJ and voltage across AJ.

A.

3.0Ω; 0.9V

B.

3.0Ω; 3.0V

C.

3.3Ω; 0.3V

D.

3.3Ω; 9.0V

Correct answer is A

E = 3.0V; Rl=10Ωm1

l = 30cm = 0.3m; R = 10Ωm1×0.3m=3Ω

EV=l1l23V=10.3

= 3×0.31=0.9V