# English Version HSC 2nd Paper 1st Chapter Physics Note

English Version HSC 2nd Paper 1st Chapter Physics Note. Thermodynamics. 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.

## English Version HSC 2nd Paper 1st Chapter Physics Note

Thermodynamics

Question No.1

The ratio of heat absorbed and heat rejected by a heat engine is 5:2. Increasing the source temperature by 110K makes the efficiency level of engine 70%. The engine absorbs 1200J heat from the source.

a. What is paraelectric constant? 1

b. “The electric potential at the center is equal to the potential at the surface of a conducting charged sphere”-explain it. 2

c. Calculate the efficiency of the heat engine. d. How to convert the engine into a reversible engine by keeping the temperature of the heat source unchanged? Explain.

The answer to the question no. 1

a. The ratio of the forces, experienced by any two charges placed at a finite distance apart in a vacuum and in any other medium is a constant. And this constant is called dielectric or paraelectric constant of that medium. Mathematically, Dielectric constant K,=Fo/Fm

Where, Fo = Force experience in a vacuum, Fm=Force experience in another medium.

b. Let the conducting sphere of radius r be charged by the +qe amount of charge. This charge will be distributed uniformly over the surface of the sphere.

As the charge distributed uniformly over the surface of the conducting sphere; so the electric field at any point inside the sphere,

E-0 [Since There is no charge inside the sphere]

The potential difference between any point on the surface and any point inside the sphere can be written as,

V-Vo=ExT where, V = Potential of any point on the surface, Vo = Potential of any point inside the sphere.

Therefore, the electric potential at any point on the surface is equal to the potential at any point inside the sphere.

c. Here,

Heat absorbed: Heat rejected,

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.

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