Which of the following is not a suitable method for reducing loss of heat from a piece of hot iron?
Wrapping it in cotton wool
painting it black
Placing it in a vacuum
Placing it on rubber supports
Keeping it in a closed wooden box
Correct answer is B
No explanation has been provided for this answer.
Heat transfer by convection in a liquid is due to the
translatory motion of the molecules of the liquid
increased vibration of the molecules of the liquid about their mean positions
expansion of the liquid as it is heated
latent heat of vaporization of the liquid
ability of the liquid to evaporate at all temperatures
Correct answer is A
No explanation has been provided for this answer.
1.38 x 106 J
2.53x104J
7.66x103J
1.38x103J
1.27 X103J
Correct answer is D
Q = mcΔθ = 0.050 x 460 x (85 - 25) = 1.38x103J
increases for a while and then decreases
decreases for a while and then increases
increases gradually
decreases gradually
remains the same
Correct answer is A
No explanation has been provided for this answer.