A cylindrical steel rod, 0.01 m in diameter and 0.2 m in length is first heated to 750 C and then immersed in a water bath at 100 C. The heat transfer coefficient is 250 W/m2K. The density, specific heat and thermal conductivity of steel are = 7801 kg/m3, c = 473 J/kgK, and k = 43 W/mK, respectively. The time required for the rod to reach 300 C is ______ seconds.

A cylindrical steel rod, 0.01 m in diameter and 0.2 m in length is fir

1.	A cylindrical steel rod, 0.01 m in diameter and 0.2 m in length is first heated to 750 C and then immersed in a water bath at 100 C. The heat transfer coefficient is 250 W/m²K. The density, specific heat and thermal conductivity of steel are = 7801 kg/m³, c = 473 J/kgK, and k = 43 W/mK, respectively. The time required for the rod to reach 300 C is ______ seconds.
A.	413.49
B.	34.49
C.	43.49
D.	None of these
Answer» D. None of these

Discussion

No Comment Found

Related MCQs

A fluid (Prandt/number, Pr = 1) at 500 K flows over a flat plate of 1.5 m length, maintained at 300 K. The velocity of the fluid is 10 m/s. Assuming kinematic viscosity. = 30 10 6 m /s, the thermal boundary layer thickness (in mm) at 0.5 m from the leading edge is ______.
A solid cylinder (surface 2) is located at the centre of a hollow sphere (surface 1). The diameter of the sphere is 1 m, while the cylinder has a diameter and length of 0.5 m each.'The radiation configuration factor F11 is
The properties of mercury at 300 K are: Density = 13529 kg/m , cp = 0.1393 kJ/kgK, dynamic viscosity = 0.1523 10 2 Ns/m and thermal conductivity = 8.540 W/mK. The Prandtl number of the mercury at 300 K is
Heat is generated uniformly in a long solid cylindrical rod (diameter =10 mm) at the rate of 4 107 W/m3. The thermal conductivity of the rod material is 25 W/mK. Under steady state conditions, the temperature ditference between the centre and the surface of the rod is 1 C.
A plane wall has a thermal conductivity of 1.15 W/mK. If the inner surface is at 1100 C and the outer surface is at 350 C, then the design thickness (in meter) of the wall to maintain a steady heat flux of 2500 W/m2 should be
A cylindrical uranium fuel rod of radius 5 mm in a nuclear is generating heat at the rate of 4 107 W/m3. The rod is cooled by a liquid (convective heat transfer coefficient 1000 W/ m2K) at 25 C. At steady state, the surface temperature (in K) of the rod is
A pipe of 25 mm outer diameter carries steam. The heat transfer coefficient between the cylinder and surroundings is 5 W/m2K. It is proposed to reduce the heat loss from the pipe by adding insulation having a thermal conductivity of 0.05 W/mK. Which one of the following statements is TRUE?
The ratios of the laminar hydrodynamic boundary layer thickness to thermal boundary layer thickness of flows of two fluids P and Q on a flat plate are 1/2 and 2 respectively. The Reynolds number based on the plate length for both the flows is 104. The Prandtl and Nusselt numbers for P are 1/8 and 35 respectively. The Prandlt and Nusselt numbers for Q are respectively
The total e-missive power of a surface is 500 W/ m2 at temperature T1 and 1200 W/m2 at temperature T2, where the temperature are in Kelvin. Assuming the e-missivity of the surface to be constant, the ratio of the temperature T1 /T2 is
If q"w = 5000 and the convection heat transfer coefficient at the pipe outlet is 1000 W/m2K, the temperature in C at the inner surface of the pipe at the outlet is

Discussion

No Comment Found

Related MCQs

Reply to Comment