Thermodynamics

The density of a substance  at  0^°C  is 10 g/cc and at  100^° C, its density is  9.7  g/cc. The coefficient of linear expansion of the substance is

• 10^-4

• 10²

• 10^-3

• 10²

The latent heat of vapourisation of water is  2240. If the work done in the process of vapourisation of 1 g is 168 J, then increase in internal energy is

• 2408 J

• 2072 J

• 2240 J

• 1904 J

An engine is working. It takes 100 calories of heat from source and leaves 80 calories of heat to sink. If the temperature of source is 127°C, then temperature of sink is

• 147°C

• 47°C

• 100^°C

• 47 K

The heat produced in a long wire is characterized by resistance, current and time through which the current passes. If the errors in measuring these quantities are respectively 1 %, 2% and 1%, then the total error in calculating the energy produced is

• 4%

• 6%

• 4/3 %

• 8%

Anatomy and Bismuth are usually used in thermocouple, because

• a constant e..m.f is produced

• higher thermo e.m.f is produced

• a negative e.m.f is produced

• lower thermo e.m.f is produced

A Carnot engine takes heat from a reservoir at 627° C and rejects heat to a sink at 27° C. Its efficiency will be

• 3/5

• 1/3

• 2/3

• 200/209

A Carnot's engine operates with source at 127°C and sink at 27°C. If the source supplies· 40 kJ of heat energy, the work done by the engine is

• 30 kJ

• 10 kJ

• 4 kJ

• 1 kJ

The velocity of sound in air at NTP is 330 m/s. What will be its value when the temperature is doubled and pressure is halved?

• 330 m/s

• 165 m/s

• 330$\sqrt{2}$ m/s

• $\frac{330}{\sqrt{2}}\mathrm{m}/\mathrm{s}$

Two gases A and B at same pressure contain a number of moles n₁ and n₂. Their volume temperature graphs are shown in the figure. Then the ratio n₁/n₂

• 1

• 1/2

• 1/3

• 3

The figure shows a P-V diagram. How does the work done in the process change with time?

• First decreases and then increases

• First increases and then decreases

• Continuously decreases

• Continuously increases