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Specific heat capacity of dry air and water vapour are 1.005 and $1.88 \mathrm{~kJ} \mathrm{~kg}^{-1} \mathrm{~K}^{-1},$ respectively. In an energy conserving system, $1 \mathrm{~kg} \mathrm{~s}^{-1}$ air at $30{ }^{\circ} \mathrm{C}$ with constant absolute humidity of $0.02 \mathrm{~kg}$ water $(\mathrm{kg}$ dry air) $^{-1}$ is heated up to $65^{\circ} \mathrm{C}$. Water at the wet bulb temperature of air is then sprayed into the air so that the final temperature of the air-water vapour mixture is $40^{\circ} \mathrm{C}$. Latent heat of vapourization of water at $70{ }^{\circ} \mathrm{C}$ and $40{ }^{\circ} \mathrm{C}$ are 2334 and $2407 \mathrm{~kJ} \mathrm{~kg}^{-1}$, respectively.The thermal energy supplied per second during heating in $\mathrm{kW}$ is
(A) 18.2
(B) 36.5
(C) 101.0
(D) 166.8



Question ID - 157316 | SaraNextGen Top Answer

Specific heat capacity of dry air and water vapour are 1.005 and $1.88 \mathrm{~kJ} \mathrm{~kg}^{-1} \mathrm{~K}^{-1},$ respectively. In an energy conserving system, $1 \mathrm{~kg} \mathrm{~s}^{-1}$ air at $30{ }^{\circ} \mathrm{C}$ with constant absolute humidity of $0.02 \mathrm{~kg}$ water $(\mathrm{kg}$ dry air) $^{-1}$ is heated up to $65^{\circ} \mathrm{C}$. Water at the wet bulb temperature of air is then sprayed into the air so that the final temperature of the air-water vapour mixture is $40^{\circ} \mathrm{C}$. Latent heat of vapourization of water at $70{ }^{\circ} \mathrm{C}$ and $40{ }^{\circ} \mathrm{C}$ are 2334 and $2407 \mathrm{~kJ} \mathrm{~kg}^{-1}$, respectively.The thermal energy supplied per second during heating in $\mathrm{kW}$ is
(A) 18.2
(B) 36.5
(C) 101.0
(D) 166.8

1 Answer
127 votes
Answer Key / Explanation : (B) -

(B) 36.5

127 votes


127