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

Which of the following parameters does not characterize the thermodynamic state of matter?

• Volume

• Temperature

• Pressure

• Work

At 27°C, a motor car tyre has a pressure of 2 atmospheres. The temperature at which the tyre suddenly burst will be : (Given: γ_air = 1.4)

• 246.1 K

• 250 K

• 246 K

• 248 K

In an isochoric process:

• ΔV = 0

• Δw = 0

• Δa = 0

• ΔT = 0