Biophysics Lecture 3 - HUE AHST 2024-2025 PDF

BIOPHYSICS FIRST LEVEL 2024-2025 Prepared By Dr. Nermin Ali Dr. Enas Lotfy Lec No. 3 Course Code: FAC-104 Page 1 Heat and Thermodynamics Page 2  Sta...

BIOPHYSICS FIRST LEVEL 2024-2025 Prepared By Dr. Nermin Ali Dr. Enas Lotfy Lec No. 3 Course Code: FAC-104 Page 1 Heat and Thermodynamics Page 2  State of materials Materials can be found basically in three different states (Solid, Liquid and gas) which can be transformed from on state or phase by absorbing or emitting heat energy. Heat capacity C: of a sample is the amount of energy needed to raise the temperature of the whole sample by 1oC. Specific heat c: of a substance is the amount of energy needed to raise the temperature of 1 gram of sample by 1oC. (heat capacity per unit mass). Phase change: the case whenever the physical characteristics of the substance change from one form to another. Page 3 Phase change and latent heat Page 4  The quantity of heat needed to change the temperature of an object can be expressed as Q = m c T Where c is the specific heat capacity defined as the quantity of heat needed to raise the temperature of 1 gm of material 1C. While (C = m c) is the heat capacity defined as the quantity of heat needed to raise the temperature of material 1C. Latent heat (L) is the quantity of heat needed to change material from phase to phase at constant temperature Q=mL Page 5 Metabolism: Energy, Heat, Work, and Power of the Body Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13  Thermal conductivity (k) Thermal conductivity defined as the amount of heat in calories or joules passing per second through a body 1cm thick, 1cm2 cross sectional area when the temperature difference is 1°C. Page 14  The thermal conductivity K describes how the temperature varies (ΔT) spatially due to the heat flow between different regions that are separated by a distance Δx. (Conversely, it also describes how much heat flows due to this spatial variation in temperature.) ∆𝑇 This relation is 𝑄 = 𝐾 𝐴 ∆𝑥 The amount of heat that flows per unit area A per unit time is called the heat flux. Page 15 Or Page 16  Thank You Course Code: FAC-104 Page 17