#### Question

a.

2k/3h

b.

3k/h

c.

2k/h

d.

k/h

Posted under Heat Transfer

#### Interact with the Community - Share Your Thoughts

Uncertain About the Answer? Seek Clarification Here.

Understand the Explanation? Include it Here.

###### Q. For an object i.e. spherical the value of critical radius would be

## Similar Questions

###### Explore Relevant Multiple Choice Questions (MCQs)

Q. A heat exchanger shell of outside radius 15 cm is to be insulated with glass wool of thermal conductivity 0.0825 W/m degree. The temperature at the surface is 280 degree Celsius and it can be assumed to remain constant after the layer of insulation has been applied to the shell. The convective film coefficient between the outside surface of glass wool and the surrounding air is estimated to be 8 W/m² degree. What is the value of critical radius?

View solution

Q. Chose the correct one with respect to critical radius of insulation

View solution

Q. A cable of 10 mm outside is to be laid in an atmosphere of 25 degree Celsius (h = 12.5 W/m² degree) and its surface temperature is likely to be 75 degree Celsius due to heat generated within it. How would the heat flow from the cable be affected if it is insulated with rubber having thermal conductivity k = 0.15 W/m degree?

View solution

Q. “If β is less than zero, then with respect to the relation k = k0 (1 + β t), conductivity depends on surface area”. True or false

View solution

Q. The temperatures on the two sides of a plane wall are t1 and t2 and thermal conductivity of the wall material is prescribed by the relation

K = k0 e^(-x/δ)

Where, k0 is constant and δ is the wall thickness. Find the relation for temperature distribution in the wall?

View solution

Q. The unit of thermal conductivity doesn’t contain which parameter?

View solution

Q. If β is greater than zero, then choose the correct statement with respect to given relation

k = k0 (1 +β t)

View solution

Q. With respect to the equation k = k0 (1 +β t) which is true if we put β = 0?

View solution

Q. The mean thermal conductivity evaluated at the arithmetic mean temperature is represented by

View solution

Q. A plane wall of thickness δ has its surfaces maintained at temperatures T₁ and T₂. The wall is made of a material whose thermal conductivity varies with temperature according to the relation k = k₀ T². Find the expression to work out the steady state heat conduction through the wall?

View solution

Q. The inner and outer surfaces of a furnace wall, 25 cm thick, are at 300 degree Celsius and 30 degree Celsius. Here thermal conductivity is given by the relation

K = (1.45 + 0.5 * 10¯⁵ t²) KJ/m hr deg

Where, t is the temperature in degree centigrade. Calculate the heat loss per square meter of the wall surface area?

View solution

Q. With variable thermal conductivity, Fourier law of heat conduction through a plane wall can be expressed as

View solution

Q. For the same amount of fabrication material and same inside capacity, the heat loss is lowest in

View solution

Q. For the same material and same temperature difference, the heat flow in terms of shape factor is given by

View solution

Q. The shape factor for complete rectangular furnace is

Where a, b and c are the inside dimensions and d x is the wall thickness

View solution

Q. Which is true regarding a complete rectangular furnace?

View solution

Q. Shape factor for sphere is

View solution

Q. The annealing furnace for continuous bar stock is open at the ends and has interior dimensions of 0.6 m * 0.6 m * 1.5 m long with a wall 0.3 m thick all around. Calculate the shape factor for the furnace?

View solution

Q. Shape factor for cylinder is

View solution

Q. For a prescribed temperature difference, bodies with the same shape factor will allow heat conduction proportional to

View solution

# Recommended Subjects

Are you eager to expand your knowledge beyond Heat Transfer? We've handpicked a range of related categories that you might find intriguing.

Click on the categories below to discover a wealth of MCQs and enrich your understanding of various subjects. Happy exploring!