Question 640: Current Electricity

Question

A 12 cm wire is given a shape of a right angled triangle ABC having sides 3 cm, 4 cm and 5 cm as shown in the figure. The resistance between two ends (AB, BC, CA) of the respective sides are measuread one by one ratio

Accepted Answer

Resistance is directly proportional to length
$${1 \over {{R_{AB}}}} = {1 \over 3} + {1 \over {4 + 5}} = {{\left( {4 + 5} ight) + 3} \over {\left( 3 ight)\left( {4 + 5} ight)}}$$
$${R_{AB}} = {{3 	imes \left( {4 + 5} ight)} \over {3 + \left( {4 + 5} ight)}} = {{27} \over {12}}$$
Similarly,
$${R_{BC}} = {{4 	imes \left( {3 + 5} ight)} \over {4 + \left( {3 + 5} ight)}} = {{32} \over {12}}$$
$${R_{AC}} = {{5 	imes \left( {3 + 4} ight)} \over {5 + \left( {3 + 4} ight)}} = {{35} \over {12}}$$
$$ 	herefore $$ R
AB
: R
BC
: R
AC
= 27 : 32 : 35

Answer

9 : 16 : 25

Answer

27 : 32 : 35

Answer

21 : 24 : 25

Answer

3 : 4 : 5

Current Electricity

A 12 cm wire is given a shape of a right angled triangle ABC having sides 3 cm, 4 cm and 5 cm as shown in the figure. The resistance between two ends (AB, BC, CA) of the respective sides are measuread one by one ratio

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