You are given resistacne wire of length 50 cm and a battery of negligible resistacne In which of the folowing cases is larges amount of heat generated
You are given resistacne wire of length 50 cm and a battery of negligible resistacne In which of the folowing cases is larges amount of heat generated?
A. When the wire is connected to the battery directly
B. When the wire is divided into two parts and both the parts are connected to the battery oin parallel
C. When the wire is divided into four parts and all the four parts are connected to the battery in parallel
D. When only hjalf of the wire is connected to the battery
1 Answers
Correct Answer - c
Let R be the resistacne of the wire
(a) `H_(1)=(V^(2)t)(R )`
(b)Resistacne of each part will be `R//2` when they are connected in parallel the resistacne will be `R//4`
Hence `H_(2)=(4V^(2)t)/(R )`
(c )In case of four wires connected in parallel the resistacne will be `R//8`
`therefore H_(3)=(8V^(2)t)/(R)`
(d) `H_(4)=(V^(2)t)/([R//2])=(2V^(2).t)/(r)`
Hence largest amount of heat will be generated in case of four parts connected in parallel.