Скачать или смотреть Physics Most important Question For NEB Class 12Sure question for board must prepare these questions

Physics Most important Question For NEB Class 12💯💯💯❤ must prepare these questions

Chapterwise Most important Questions According To new Syllabus of Physics Class 12

Most important questions From Fluid Statics

1. What is surface tension? Does it depend on surface area of fluid? Use the concept to find excess pressure in fluid drop to calculate surface tension in capillary rise method. [1+1+3]

2. State pascals law. How fluid pressure is independent of area of container. To what height should a cylindrical vessel be filled with a liquid to make the force on the side of vessel will be equal to the force on the bottom of the vessel. [1+2+2]

3. State pascals law. Prove that fluid pressure is = ℎ where the symbol carries usual meaning. A ′′ − of horizontal portion 8 cm having uniform cross-section is filled with water from one end and glycerol (′ = 0.8 SHAPE \* MERGEFORMAT ′) is powered from other end such that each fluid occupied 22cm of the tube. Find the position of common surface of two liquids. [1+2+2]

4. State Archimedes principle. Is it applicable for floating object? A piece of alloy of copper ( = 8.9 ) and zinc ( = 7.1 ) weighs 12.9 g in air completely immersed in water resulting weight 11.3 g in water. Find the fraction of mass metal in alloy. [1+1+3]

5. State law of floatation. Is body in equilibrium in floatation? A piece of cube of wood supporting a 200 g mass just floats in water. When the mass is removed, the cube rises by 2 cm. what is the size of cube? [1+2+2]

6. Define streamlined flow. How does streamlined flow turns into turbulent? It is desired to design an airplane with a lift 1000N per meter square with the wing area. If the velocity of air passing from lower surface of wing is 150 SHAPE \* MERGEFORMAT , what should be the velocity at upper surface. Given that = 1.3 −3. [1+1+3]

7. What is viscosity of fluid. How does it change with temperature? An air bubble of radius 1 cm rises with constant speed of 3.5 mm/s through a liquid of density of 1.75 × 103 SHAPE \* MERGEFORMAT 3. find the coefficient of viscosity of liquid. Neglect the density of air. [1+1+3]

Most important questions From First law of thermodynamics

1. What is meant by thermodynamical variable? What comprises internal energy of system? Water falls from 350 high, find the temperature change assuming that the whole of energy due to fall converted into heat. = 4200−1. [1+2+2]

2. What is molar heat capacity of gas? Why is the molar heat capacity at constant pressure more that constant volume? 105 calories of heat is required to raise the temperature of 3 moles of ideal gas at constant pressure from 25 C to 30 C. calculate the amount of heat required to raise the temperature of same ga through the same range of temperature at constant volume. [1+2+2]

3. what do you mean by isothermal process. Derive relation to find work done by gas expanded from pressure ′1′ to ′2′ at constant temperature ′′. If 5 moles of gas at 1 atm is expanded from 50 liter from 5 liter at constant temperature of 20 C. find the work done by the gas. [1+2+2]

4. State the significance of first law of thermodynamics. In constant -volume process, = holds true but in constant-pressure process = is not true, why? Two mole of ideal gas is heated from 250 to 500 at constant pressure. Draw P-V diagram for the process and calculate the work done. [1+2+1+1]

5. State the significance P-V diagram in thermodynamics. The P-V diagram alongside shows a process involving 0.45 mol of ideal gas. What is the temperature at point ′′ and ′′. How much work was done by or on the gas in this process. How much heat is to be supplied to increase the internal energy of gas by 15000J? [2+3]

6. What do you mean by adiabatic process. The equation of state of adiabatic process can be expressed as = . Using this relation show that the work done in the process is given by = SHAPE \* MERGEFORMAT −1 (1 − 2) where the symbol carries usual meaning. During adiabatic expansion of 0.5 mol of Argon gas the temperature falls to 70 from 520, find the work done.