Question 634: Current Electricity

Question

The sliding contact C is at one fourth of the length of the potentiometer wire (AB) from A as shown in the circuit diagram. If the resistance of the wire AB is R0, then the potential drop (V) across the resistor R is

Accepted Answer

Equivalent resistance across point AC
$${R_{AC}} = {{{{{R_0}} \over 4} 	imes R} \over {{{{R_0}} \over 4} + R}} = {{R{R_0}} \over {{R_0} + 4R}}$$
From voltage divider rule
$${V_{AC}} = {{{R_{AC}}} \over {{R_{AC}} + {R_{CB}}}}{V_0} = {{{{R{R_0}} \over {{R_0} + 4R}}{V_0}} \over {{{R{R_0}} \over {{R_0} + 4R}} + {{3{R_0}} \over 4}}}$$
$$ = {{4R{R_0}{V_0}} \over {4R{R_0} + 3R_0^2 + 12R{R_0}}} = {{4R{V_0}} \over {3{R_0} + 16R}}$$

Answer

$${{2{V_0}R} \over {2{R_0} + 3R}}$$

Answer

$${{4{V_0}R} \over {3{R_0} + 16R}}$$

Answer

$${{4{V_0}R} \over {3{R_0} + R}}$$

Answer

$${{2{V_0}R} \over {4{R_0} + R}}$$

Current Electricity

The sliding contact C is at one fourth of the length of the potentiometer wire (AB) from A as shown in the circuit diagram. If the resistance of the wire AB is R0, then the potential drop (V) across the resistor R is

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