Specific latent heats of fusion and vaporization - Jamb Physics Past Questions and Answers

Question 11:

• JAMB 1987

Calculate the amount of heat required to convert 2kg of ice at 2^oC to water at 0^oC. [specific heat capacity of ice = 2090Jkg^-1oC^-1, specific latent heat of fusion of ice = 333kJkg^-1]

A. 666J
B. 8360J
C. 666 000J
D. 674 360J

Question 12:

• JAMB 1989

An electric heater is used to melt a block of ice of mass 1.5kg. If the heater is powered by a 12V battery and a current of 20A flows through the coil, calculate the time taken to melt the block of ice at 0^oC. [specific latent heat of fusion of ice = 336 x 10³Jkg^-1]

A. 76.0min
B. 35.0min
C. 21.0min
D. 2.9min

Question 13:

• JAMB 1997

A heating coil rated at 100W is used to boil off 0.5kg of boiling water. The time taken to boil off the water is [specific latent heat of vaporization of water = 2.3 x 10⁶Jkg^-1]

A. 1.15 x 10⁹ s
B. 1.15 x 10⁷ s
C. 1.15 x 10⁵ s
D. 1.15 x 10⁴ s

Question 14:

• JAMB 1998

How many grams of water at 17^oC must be added to 42g of ice at 0^oC to melt the ice completely? [specific latent heat of fusion of ice = 3.4 x 10⁵Jkg^-1, specific heat capacity of water = 4200Jkg^-1k^-1]

A. 200g
B. 300g
C. 320g
D. 400g

Question 15:

• JAMB 2009

A heating coil rated 1000 W is used to boil off completely 2 kg of boiling water. the time required to boil of the water is_______
[Special latent heat of Vaporization of water = 2.3 x 10⁶ Jkg^-1]

A. 1.15 x 10⁴s
B. 1.15 x 10³s
C. 4.6 x 10⁴s
D. 4.6 x 10³s