## Heat Transfer Miscellaneous

#### Heat-Transfer

1. Match the property with their units
 Property Units A. Bulk modulus 1. W/s B. Thermal conductivity 2. N/m2 C. Heat transfer coefficient 3. N/m3 D. Heat flow rate 4. W 5. W/mK 6. W/m2K

1. NA

##### Correct Option: B

NA

1. Thermal conductivity is lower for

1. NA

##### Correct Option: B

NA

1. A solid sphere 1 of radius r is placed inside a hollow, closed hemispherical surface 2 of radius 4r. The shape factor F is,

1. f 11 + f 12 = 1
∴ f 12 = 1
f 21 A2 = f 12 A1

 ∴ f21 = f12A1 = 1 × 4πr2 = V = 1 A2 k (1 / 2)4π(4r)2 + π(4r)2 12

##### Correct Option: A

f 11 + f 12 = 1
∴ f 12 = 1
f 21 A2 = f 12 A1

 ∴ f21 = f12A1 = 1 × 4πr2 = V = 1 A2 k (1 / 2)4π(4r)2 + π(4r)2 12

1. A diffuse radiation surface has

##### Correct Option: A

1. What is the value of the view factor for two inclined flat plates having common edge of equal length and wlth an angle of 20 degrees?

1.  F12 = F21 = 1 - sin θ 2

 = 1 - sin 20° = 0.826 2

##### Correct Option: A

 F12 = F21 = 1 - sin θ 2

 = 1 - sin 20° = 0.826 2