Answer to Question #51931 in Field Theory for vi

Question

16 A student tries to determine the specific latent heat of vaporisation of a liquid by an electrical method. A heater is used to boil the liquid and when the liquid is boiling, the mass of liquid vaporised per second is measured at two different powers for the heater. At the power of 40 W and 80 W, the liquid is vaporised at the rate of 0.0417
kgs−1
and 0.0893
kgs−1
respectively. What is the best estimate of the specific latent heat of vaporisation of the liquid?

840Jkg−1

896Jkg−1

928Jkg−1

959Jkg−1
17 The temperature 47.12 °C is equivalent to
320.28 K
320.27 K
-226.03 K
-226.04 K
18 A gas cylinder is fitted with a safety valve which releases a gas when the pressure inside the cylinder reaches
2.0x106Pa
. Given the maximum mass of this gas that the cylinder can hold at 10 °C is 15 kg, what would be the maximum mass at
30∘C
?
5 kg
14 kg
20 kg
45 kg