Units and Measurements — Physics STD 11 Science — Question

Answer the following questions based on the P-T phase diagram of carbon dioxide

1. At what temperature and pressure can the solid, liquid and vapour phases of CO₂ co-exist in equilibrium ?
2. What is the effect of decrease of pressure on the fusion and boiling point of CO₂?
3. What are the critical temperature and pressure for CO₂? What is their significance?
4. Is CO₂ solid, liquid or gas at (a) –70 °C under 1 atm, (b) –60 °C under 10 atm, 15 °C under 56 atm?

Which of the following length measurement is most accurate and why?

1. 2.0cm
2. 2.00cm
3. 2.000cm

Which of the following examples represent (nearly) simple harmonic motion and which represent periodic but not simple harmonic motion?

General vibrations of a polyatomic molecule about its equilibrium position.

Why do spring balance shows wrong readings after they have been used for a long time?

If the angle of friction is 30° then what is coefficient of static friction?

The free electrons in a conducting wire are in constant thermal motion. If such a wire, carrying no current, is placed in a magnetic field, is there a magnetic force on each free electron? On the wire?

Pick out the only vector quantity in the following list :
Temperature, pressure, impulse, time, power, total path length, energy, gravitational potential, coefficient of friction, charge.

When a particle moves with constant velocity, its average velocity, its instantaneous velocity and its speed are all equal. Comment on this statement.

The total energy of particle remains in simple harmonic motion.