Derive the dimension of specific heat.
Answers
Answer:
The specific heat capacity of a substance is the heat capacity of a sample of the substance divided by the mass of the sample. Informally, it is the amount of energy that must be added, in the form of heat, to one unit of mass of the substance in order to cause an increase of one unit in its temperature. The SI unit of specific heat is joule per kelvin and kilogram, J/(K kg).[1][2] For example, at a temperature of 25 °C (the specific heat capacity can vary with the temperature), the heat required to raise the temperature of 1 kg of water by 1 K (equivalent to 1 °C) is 4179.6 joules, meaning that the specific heat of water is 4179.6 J·kg−1·K−1.[3]
The specific heat often varies with temperature, and is different for each state of matter. Liquid water has one of the highest specific heats among common substances, about 4182 J/K/kg at 20 °C; but that of ice just below 0 °C is only 2093 J/K/kg. The specific heats of iron, granite, oak wood, and hydrogen gas are about 449, 790, 2400, and 14300 J/K/kg, respectively. While the substance is undergoing a phase transition, such as melting or boiling, its specific heat is technically infinite, because the heat goes into changing its state rather than raising its temperature.
The specific heat of a substance, especially a gas, may be significantly higher when it is allowed to expand as it is heated (specific heat at constant pressure) than when is heated in a closed vessel that prevents expansion (specific heat at constant volume). These two values are usually denoted by {\displaystyle c_{P}} c_{P} and {\displaystyle c_{V}} c_{V}, respectively; their quotient {\displaystyle \gamma =c_{P}/c_{V}} {\displaystyle \gamma =c_{P}/c_{V}}is the heat capacity ratio.
In some contexts, however, the term specific heat capacity (or specific heat) may refer to the ratio between the specific heats of a substance at a given temperature and of a reference substance at a reference temperature, such as water at 15 °C;[4] much in the fashion of specific gravity.
Specific heat relates to other intensive measures of heat capacity with other denominators. If the amount of substance is measured as a number of moles, one gets the molar heat capacity instead (whose SI unit is joule per kelvin per mole, J/K/mol). If the amount is taken to be the volume of the sample (as is sometimes done in engineering), one gets the volumetric heat capacity (whose SI unit is joule per kelvin per cubic meter, J/K/m3).
One of the first scientists to use the concept was Joseph Black, 18th-century medical doctor and professor of Medicine at Glasgow University. He measured the specific heat of many substances, using the term capacity for heat.
The dimensional formula of Specific Heat Capacity is given by,
M0 L2 T-2 K-1
Where,
M = Mass
K = Temperature
L = Length
T = Time
Derivation
Specific Heat Capacity (C) = Heat × [Mass × Temperature]-1. . . . (1)
The dimensional formula of mass and temperature = [M1 L0 T0] and [M0 L0 T0 K1] . . . .(2)
Since, the dimensions of Heat Energy = Dimensions of Work Done
And, Work = Force × displacement
= M × a × displacement = [M] × [M1 L1 T-2] × [L]
∴ the dimensional formula of Heat energy = M1 L2 T-2 . . . . (3)
On substituting equation (2) and (3) in equation (1) we get,
Specific Heat Capacity = Heat × [Mass × Temperature]-1
Or, C = [M1 L2 T-2] × [M1 L0 T0]-1 × [M0 L0 T0 K1]-1 = [M0 L2 T-2 K-1].
Therefore, specific heat capacity is dimensionally represented as [M0 L2 T-2 K-1].
⇒ Check Other Dimensional Formulas:
Dimensions of Pressure Gradient
Dimensions of Current Density
Dimensions of Impedance
Dimensions of Linear Density
Dimensions of Rotational Kinetic Energy
JEE Related LinksIIT JEE MainsJEE Main Online Paper 2017Books for JEE AdvancedPhysics for JEE AdvancedHoffmann Bromamide Degradation ReactionJEE Main 2019 Exam PatternEnergy Stored in a CapacitorJEE Advanced Eligibility CriteriaJEE Advanced Marking SchemeMathematics Syllabus




Join BYJU'S JEE Learning Program
Submit
Leave a Comment
Your email address will not be published. Required fields are marked *
Comment
Name *
Email *
COURSES
CBSE
ICSE
CAT
IAS
JEE
NEET
Commerce
Bank Exam
NCERT
EXAMS
CAT Exam
IAS Exam
UPSC Syllabus
UPSC 2020
Government Exams
JEE Main
RESOURCES
Blog
Videos
CBSE Sample Papers
CBSE Question Papers
EXAM PREPARATION
Free CAT Prep
Free IAS Prep
Maths
Physics
Chemistry
Biology
COMPANY
About Us
Contact Us
Student Feedback
Investors
Careers
BYJU'S in Media
Students Stories - The Learning Tree
Life at BYJU'S
FOLLOW US
Free Textbook Solutions
NCERT Solutions
NCERT Exemplar
NCERT Solutions for Class 6
NCERT Solutions for Class 7
NCERT Solutions for Class 8
NCERT Solutions for Class 9
NCERT Solutions for Class 10
NCERT Solutions for Class 10 Maths
NCERT Solutions for Class 11
NCERT Solutions for Class 12
RD Sharma Solutions
RS Aggarwal Solutions
ICSE Selina Solutions
State Boards
Maharashtra
Gujarat
Tamil Nadu
Karnataka
Kerala
Andhra Pradesh
Telangana
Uttar Pradesh
Bihar
Rajasthan
Madhya Pradesh
Disclaimer | Privacy Policy | Terms of Services | Sitemap
© 2020, BYJU'S. All rights reserved.