ECAT MCQs

Thermal radiation can travel through vacuum.
Its intensity increases strongly with absolute temperature.

The ideal gas model simplifies real gas behavior.
It works best at low pressure and high temperature.

Continuity gives A₁v₁=A₂v₂.
V₂=0.06×2/0.02 = 6 m/s.

For an isothermal ideal-gas process, PV is constant.
Reducing volume raises pressure.

Strain is extension divided by original length.
0.004/2 = 0.002.

At fixed pressure, heating an ideal gas increases its volume.
Temperature must be measured on an absolute scale.

Stress is force divided by cross-sectional area.
1000/0.005 = 200,000 Pa.

Young's modulus is stress divided by strain.
2×10^8 / 0.001 = 2×10^11 Pa.

Hooke's law magnitude gives k=F/x.
K=20/0.04 = 500 N/m.

Temperature indicates how energetic particle motion is on average.
It determines the direction of spontaneous heat transfer.

Heat is energy in transit between systems.
It flows spontaneously from higher to lower temperature.

Systems in thermal equilibrium have the same temperature.
This idea underlies the zeroth law of thermodynamics.