# HSC EV 1st Paper 1st Chapter Physics Note. Physical World and Measurement

HSC EV 1st Paper 1st Chapter Physics Note. Physical World and Measurement. The physics is one of the oldest academic disciplines, perhaps the oldest through the inclusion of astronomy. In the last two millennia, physics was a part of natural philosophy, chemistry, certain branches of mathematics and biology, but during the scientific revolution in the 17th century, the natural sciences emerged as unique in its own right research programs. Physics intersects with many interdisciplinary areas of research, such as Biophysics and quantum chemistry, and physics limits are not rigidly defined. New ideas in physics often explain the fundamentals of other sciences mechanisms, to open new avenues of research in areas such as mathematics and philosophy.

Ques. 1 An engineer establishes a heat engine which follows Carnot theorem and one-mole diatomic gas is used as a working substance in that engine. It ejects 1296 J heat to the sink during each cycle. It completes a cycle along ABCDA path in a P-V diagram. Pressure and volume of different points of the P-V diagram are as follows:

a. What is breaking stress?                                                                   1

b. Explain entropy with respect to the Kelvin’ 2nd law of thermodynamics. 2

What will be the amount of work done for BC step?                                 3

Is it possible to calculate the efficiency of the engine? – Analyze.             4

The answer to the question no. 1

a. The smallest force applied per unit area, for which any in the area, for which any interval terms or breaks is called the breaking stress.

b. Kelvin’s statement of the 2nd law of then thermodynamics is —

It is impossible to convert the heat from a single source into work without any other effect. One implication of this second law is that heat flows spontaneously from a hotter region to a cooler region, but will not flow spontaneously the other way. This applies to anything that flows: it will naturally flow downhill rather than uphill.

Many processes are irreversible, and any irreversible process the most important implications of the second law is that it indicates which way time goes-time naturally flows in a way that increases disorder. And entropy is the measure of the disorder of a system. So, in any spontaneous process, entropy increases.

Physical World and Measurement

Physics is one of the oldest academic disciplines and, through its inclusion of astronomy, perhaps the oldest. Over the last two millennia, physics, chemistry, biology, and certain branches of mathematics were a part of natural philosophy, but during the scientific revolution in the 17th century, these natural sciences emerged as unique research endeavors in their own right. Physics intersects with many interdisciplinary areas of research, such as biophysics and quantum chemistry, and the boundaries of physics are not rigidly defined. New ideas in physics often explain the fundamental mechanisms studied by other sciences and suggest new avenues of research in academic disciplines such as mathematics and philosophy.

teachingbd24.com is such a website where you will get all kinds of necessary information regarding educational notes, suggestions and question patterns of schools, colleges, and madrasas. Particularly, you will get here special notes of physics that will be immensely useful to both students and teachers. The builder of the website is Mr. Md. Shah Jamal who has been serving for 32 years as an Assistant Professor of Physics at BAF Shaheen College Dhaka. He expects that this website will meet up all the needs of Bengali version learners /students. He has requested concerned students and teachers to spread this website home and abroad.