  # ISRO Scientist or Engineer Refrigeration & Air-Conditioning 2013

Instructions

For the following questions answer them individually

Question 71

# If the inner and outer walls of a hollow sphere having surface areas of $$A_1$$ and $$A_2$$ and inner and outer radii $$r_1$$ and $$r_2$$ are Maintained at temperatures $$t_1$$ and $$t_2$$, then rate of heat flow will be Question 72

# Water is boiled at 1 atm pressure in a coffee maker equipped with an immersion-type electric heating element. The coffee maker initially contains 1 kg of water. Once boiling jstarted, it is observed that half of the water in the coffee maker evaporated in 18 minutes. If the heat loss from the coffee maker is negligible, the power rating of the heating element is Question 73

# Ductility of steel is reduced by Question 74

# Machining of cast iron material is mostly performed Question 75

# Asine bar is used for the accurate measurement of Question 76

# The process used to improve fatigue resistance of the metal by setting up compressive stresses in its surface, is known as Question 77

# The instrument which has all the features of try-square, bevel protractor, rule and scriber is Question 78

# Vector C is perpendicular to vectors A and B both, then: Question 79

# An unbiased dice is tossed twice. Find the Probability of getting 4,5 or 6 on the first toss and a 1,2,3 or 4 on the second toss Question 80

# For the given characteristic matrix [A], determinethe Eigen Values :-$$A = \begin{bmatrix}4 & 1 \\1 & 4 \end{bmatrix}$$ OR