A. Q ∝ T2
B. Q ∝ T4
C. Q ∝ T3
D. None of these
Related Mcqs:
- If the thermal conductivity of a wall material is independent of temperature, the steady state temperature distribution in the very large thin plane wall having steady, uniform surface temperature follows _____________ law?
A. Parabolic
B. Hyperbolic
C. Linear
D. Logarithmic - If the thermal conductivity of a wall material is independent of temperature, the steady state temperature distribution in the very large thin plane wall having steady, uniform surface temperature follows ____________ law?
A. Hyperbolic
B. Parabolic
C. Linear
D. Logarithmic - A long iron rod initially at a temperature of 20°C has one end dipped in boiling water (100°C) at time, t = 0. The curved surface of the rod is insulated so that heat conduction is one dimensional in the axial direction. The temperature at a distance 100 mm from the dipped end becomes 40°C at time, t = 200 s. The same temperature is achieved at a distance of 200 mm from the dipped end at time ___________________?
A. t = 283 s
B. t = 356 s
C. t = 400 s
D. t = 800 s - Wavelength corresponding to the maximum energy is inversely proportional to the absolute temperature. This is ________________ law?
A. Stefan’s
B. Dalton’s
C. Wien’s
D. Kirchoff’s - Stefan-Boltzmann law which describes the radiation heat transfer states that, it is proportional to (where, t = temperature in °C T = absolute temperature in ° K) ?
A. t4
B. T4
C. 1/t4
D. 1/T4 - Out of 100 kcal/second of incident radiant energy on the surface of a thermally transparent body, 300 kcal/second is reflected back. If the transmissivity of the body is 0.25, the emissivity of the surface will be_________________?
A. 0.35
B. 0.45
C. 0.55
D. 0.85 - The inner wall of a furnace is at a temperature of 700°C. The composite wall is made of two substances, 10 and 20 cm thick with thermal conductivities of 0.05 and 0.1 W.m-1.°C- 1 respectively. The ambient air is at 30°C and the heat transfer co-efficient between the outer surface of wall and air is 20 W.m-2.°C-1. The rate of heat loss from the outer surface in W.m-2is__________________?
A. 165.4
B. 167.5
C. 172.5
D. 175 - The thermal radiative flux from a surface of emissivity = 0.4 is 22.68 kW/m2. The approximate surface temperature (K) is (Stefan-Boltzmann constant = 5.67 × 10-8 W/m2.K4) ?
A. 1000
B. 727
C. 800
D. 1200 - Terminal point temperature differences between fluids in case of a heat exchanger is termed as__________________?
A. Approach
B. Log mean temperature difference
C. Arithmetic mean temperature difference
D. Geometric mean temperature difference - In case of _______________ boiling, the liquid temperature is below the saturation temperature and the boiling takes place in the vicinity of the heated surface?
A. Nucleate
B. Local
C. Pool
D. Saturated
