If heat conducted into the element at plane x is Q X = – k A C (d t/d x) X. Then heat conducted out of the element at plane (x + d x) is

– 2k A C d/d x (t + d t/d x (d x))

– k A C d/d x (t + d t/d x (d x))

– 3k A C d/d x (t + d t/d x (d x))

– 4k A C d/d x (t + d t/d x (d x))

Explore topic-wise MCQs in Heat Transfer Questions and Answers.

This section includes 2 Mcqs, each offering curated multiple-choice questions to sharpen your Heat Transfer Questions and Answers knowledge and support exam preparation. Choose a topic below to get started.

1.	A heating unit is made in the form of a vertical tube of 50 mm outside diameter and 1.2 m height. The tube is fitted with 20 steel fins of rectangular section with height 40 mm and thickness 2.5 mm. The temperature at the base of fin is 75 degree Celsius, the surrounding air temperature is 20 degree Celsius and the heat transfer coefficient between the fin as well as the tube surface and the surrounding air is 9.5 W/m2 K. If thermal conductivity of the fin material is 55 W/m K, find the amount of heat transferred from the tube without fin
A.	98.44 W
B.	88.44 W
C.	78.44 W
D.	68.44 W
Answer» B. 88.44 W

Discussion

2.	If heat conducted into the element at plane x is Q X = – k A C (d t/d x) X. Then heat conducted out of the element at plane (x + d x) is
A.	– 2k A C d/d x (t + d t/d x (d x))
B.	– k A C d/d x (t + d t/d x (d x))
C.	– 3k A C d/d x (t + d t/d x (d x))
D.	– 4k A C d/d x (t + d t/d x (d x))
Answer» C. – 3k A C d/d x (t + d t/d x (d x))

Discussion