Question 487: Current Electricity

Question

The potentiometer wire is 5 m long and potential difference of 4 V is maintained between the ends. The e.m.f. of the cell which balances against a length of 200 cm of the potentiometer wire is

Accepted Answer

Step 1: Data given
Length of potentiometer wire, $L = 5 \,	ext{m} = 500 \,	ext{cm}$
Potential difference across wire, $V = 4 \,	ext{V}$
Balance length = $200 \,	ext{cm}$
Step 2: Potential gradient (voltage per cm)
$ 	ext{Potential gradient} = \frac{V}{L} = \frac{4}{500 \,	ext{cm}} = 0.008 \,	ext{V/cm} $
Step 3: E.M.F of the cell
$ E = (	ext{potential gradient}) 	imes (	ext{balancing length}) $
$ E = 0.008 \,	ext{V/cm} 	imes 200 \,	ext{cm} $
$ E = 1.6 \,	ext{V} $
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Final Answer: Option D (1.6 V)

Answer

0.4 V

Answer

0.8 V

Answer

1.2 V

Answer

1.6 V

Current Electricity

The potentiometer wire is 5 m long and potential difference of 4 V is maintained between the ends. The e.m.f. of the cell which balances against a length of 200 cm of the potentiometer wire is

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