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?


43.80 W per meter length


53.80 W per meter length


63.80 W per meter length


73.80 W per meter length

Answer: (b).53.80 W per meter length

Interact with the Community - Share Your Thoughts

Uncertain About the Answer? Seek Clarification Here.

Understand the Explanation? Include it Here.

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...

Similar Questions

Explore Relevant Multiple Choice Questions (MCQs)

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

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?

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

Q. If β is greater than zero, then choose the correct statement with respect to given relation
k = k0 (1 +β t)

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

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

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?

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?

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

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

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

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

Q. Which is true regarding a complete rectangular furnace?

Q. Shape factor for sphere is

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?

Q. Shape factor for cylinder is

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

Q. Shape factor for plane wall is equal to

Q. “All the factors relating to geometry of the sections are grouped together into a multiple constant called the shape factor” True or false

Q. The following data pertains to a hollow cylinder and a hollow sphere made of same material and having the same temperature drop over the wall thickness

Inside radius = 0.1 m and outside surface area = 1 square meter

If the outside radius for both the geometrics is same, calculate the ratio of heat flow in the cylinder to that of sphere?

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!