Question
What is thermal resistance of a conductor? Write its unit and dimensional formula.
Solution
Thermal resistance is the hindrance offered by a body to the flow of heat.
Consider a conductor of length l, the area of cross-section A and thermal conductivity K.
When the two ends of conductor are kept at temperature difference
, then the rate of flow of heat is given by,
Consider a conductor of length l, the area of cross-section A and thermal conductivity K.
When the two ends of conductor are kept at temperature difference
, then the rate of flow of heat is given by,i.e., for a given conductor, the rate of flow of heat is directly proportional to the temperature difference across the length of is conductance.
The reciprocal of thermal conductance i.e. l/KA is called thermal resistance.
The unit of thermal resistance is J–1 Ks.
The dimensional formula is [M–1L–2T–3K1]
