FINS MULTIPLE CHOICE QUESTIONS (MCQ) WITH ANSWERS

 

FINS MULTIPLE CHOICE QUESTIONS

(MCQ) WITH ANSWERS 

MCQ on fins increases knowledge and

understanding. It increases the depth of

clarity. It is then easy to apply the

fundamentals in design and use of fins

in various practical applications.

Fig. Types of fins

Fig. Details of a Rectangular Fin

Fig. Different Cases of Fins

Fig. Heat lost by a fin

Fig. Temperature Variation in a fin

 

  1. Fin increases the rate of heat transfer by increasing the

(a) Temperature difference

(b) Surface area

(c) Film coefficient

(d)None

Ans: (b)

2. The fin efficiency  of infinite length is

(a)Infinity

(b) 100 %

(c) zero

(d) None

Ans: (c)

3. In case of a fin, q.max is

(a) hAc(tb–ta)

(b)  hAs (tb–ta)

(c) -kAc Ət/Əx

(d) None

ANS:   (b)

4. Efficiency of the fin is

(a) q. with fin / q. without fin

(b) q. without fin/ q. with fin

(c) q. without fin/ q. max

(d) None,

ANS: ©

5. Boundary conditions for a fin of infinite length are

(a) θ=θ0=(tb–ta) at x=0 and  θ=θL=(tb–ta) at x=L

(b) θ=θ0=(tb–ta) at x=0 and  θ=0 =(tb–ta) at x=∝

© θ=θ0=(tb–ta) at x=0 and  θ=θ=ta at x=∝

(d) None

ANS:  (b)

6. Two boundary conditions for a fin of finite length with tip insulated are

(a) θ=θ0=(tb–ta) at x=0 and  θ=θL=(tb–ta) at x=L

(b) θ=θ0=(tb–ta) at x=0 and  θ=θL=tb at x=L

© θ=θ0=(tb–ta) at x=0 and  Əθ/Əx =0 at x=L

(d) None

ANS: (c)

7. To increase the effectiveness of a fin, the film coefficient ‘h’ should be

(a) high

(b) less

(c) equal to 100

(d)None

ANS:  (b)

8. Minimum effectiveness of a fin should be

(a) > (10)0.5

(b) > (20)0.5

(c) > (5)0.5

(d) None

Ans:    (c)

9.The relation between effectiveness and efficiency of a fin is

(a) η= ε As/Ac

(b) η= ε Ac/As

(c) ε = η As/Ac

(d) None

ANS: (b)

  1. Efficiency for a fin of finite length with tip insulated is

(a) Cosh(mL)/mL,

(b) Sinh(mL)/mL

(c) Cosh(mL)/Sinh(mL)

(d) None

ANS:  (d)

11. Which fluid is best on the outer surface of a fin

(a)Any  fluid

(b) Liquid

(c) Gas

(d) None

ANS: (c)

12. Parameter ‘m’ of a fin is

(a) (k Ac/h P)0.5

(b) (PAc/hk)0.5

(c) (hP/kAc)0.5

(d) None

ANS:  (c)

13. Temperature distribution in case of a fin of infinite length is

(a) linear

(b) Parabolic

(c) Exponential

(d) None

ANS:  (c)

14. Effectiveness of a fin be

(a) <1

(b) =1

(c) >1

(d) None

ANS:(c)

15. What is the purpose of using fins in heat transfer?

    1.  Increase the rate of heat transfer

    2.  Decrease the rate of heat transfer

    3. To maintain constant rate of heat transfer

    4. None

Ans: (a)

16. Temperature at the fin tip of uniform cross section will be

    1. Minimum

    2. Maximum

    3. Temperature of the base

    4. None

Ans: (i)

17. In heat transfer through fins, the entire fin surface will be

(a) Same temperature

(b)Variable temperatures

(c)Base temperature

(d)None

Ans: (b)

18. Which analysis is the easiest among the three cases of the fins

    1.  Infinite length fin

    2.  Finite length fin with tip insulated

    3. A fin of finite length

    4. None

Ans: (a)

19. In which case the efficiency of the fin will be maximum

  1.  Infinite length fin

  2. Fin of finite length with tip insulated

  3.  Finite length fin

  4. None

Ans: (c)

 

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