H c verma questions from concepts in physics gases temperature la gastronomie


QUESTIONS FOR SHORT ANSWER 3. 4. 1. If two bodies are in thermal equilibrium in one frame, will they be in thermal equilibrium in all frames ? 2. Does the temperature of a body depend on the frame from which it is observed ? It is heard sometimes that mercury is used in defining the temperature scale because it expands uniformly with the temperature. If the temperature scale is not yet defined, is it logical to say that a substance expands uniformly with the temperature ? In defining the ideal gas temperature scale, it is assumed that the pressure of the gas at constant volume is proportional to the temperature T. How can we verify whether this is true or not ? Are we using the kin etic theory of gases ? Are we using the experimental result that the pressure is proportional to temperature ? Can the bulb of a thermometer be made of an adiabatic wall? Why do marine animals live deep inside a lake when the surface of the lake freezes ? 7. The length of a brass rod is found to be smaller on a hot summer day than on a cold winter day as measured 5.

as seen from the ground ? (a) kinetic (b) total (c) mechanical (d) internal. 4. In which of the following pairs of temperature scales, the size of a degree is identical ? (a) mercury scale and ideal gas scale (b) Celsius scale and mercury scale (c) Celsius scale and ideal gas scale (d) ideal gas scale and absolute scale. 5. A solid object is placed in water contained in an adiabatic container for some time. The temperature of water falls during the period and there is no appreciable change in the shape of the object. The temperature of the solid object (a) must have increased (b) must have decreased (c) may have increased (d) may have remained constant. 6. As the temperature is increased, the time period of a pendulum (a) increases proportionately with temperature (b) increases (c) decreases (d) remains constant. EXERCISES 1. The s team point and the ice point of a mercury thermometer are marked as 80° and 20°. What will be the temperature in centigrade mercury scale when this thermometer reads 32° ? 2. A constant volume thermometer registers a pressure of 1"500 x 10 ‘ Pa at the triple point of water and a pressure of 2-050 x 10 Pa at the normal boi ling point . What is the temperature at the normal boiling point ? 3. A ga s thermomete r measures the temperature from th e variation of pressure of a sample of gas. If the pressure measured at the melting point of lead is 2’20 times the pressure measured at the triple point of water, find the melting point of lead. 4. The pr essure measured by a constant volume gas thermometer is 40 kPa at the triple point of water. What will be the pressure measured at the boiling point of water (100°C) ? 5. The pressure of the gas in a constant volume gas ther momet er is 70 kPa at the ice point. Find the pressure at the steam point. 6. The pressures of the gas in a constant volume gas thermometer are 80 cm, 90 cm and 100 cm of mercury at the ice point, the steam point and in a heated wax bath respectively. Find the temperature of the wax bath. 7. In a Callender’s compensated constant pressure air thermometer, the volume of the bulb is 1800 cc. When the bulb is kept immersec’ in a vessel, 200 cc of mercury has to be poured out. Calculate the temperature of the vessel. 8. A platinum resistance thermometer reads 0° when its resistan ce is 80 Q . and 100° when its resis tance is 90 Q. Find the temperature at the platinum scale at which the resist ance is 8 G Q.