Change of State - Jamb Physics Past Questions and Answers

Question 16:

• JAMB 1983

An electric current of 3Aflowing through an electric heating elements of resistance 20 embedded in 1,000g of an oil raises the temperature of the oil by 10^oC in 10 seconds then the specific heat capacity of the oil is

A. 1.8Jg^-1oC
B. 0.6Jg^-1oC
C. 0.18Jg^-1oC
D. 18Jg^-1oC
E. 0.06Jg^-1oC

Question 17:

• JAMB 1983

The specific latent heat of vaporization of a substance is always

A. Less than its specific latent heat of fusion
B. Greater than its specific heat of fusion
C. Equal to its specific latent heat of fusion
D. All of the above depending on the nature of the substance
E. None of the above

Question 18:

• JAMB 1984

All the heat generated in a 5\(\Omega\) resistor by 2A flowing for 30 seconds is used to evaporate 5g of a liquid at its boiling point. Which of the following is the correct value of the specific latent heat of the liquid?

A. 120J
B. 60Jg^-1
C. 120Jg^-1
D. 1500J
E. 1500Jg^-1

Question 19:

• JAMB 1984

Heat is supplied uniformly at the rate of 100W to 1.0 x 10^-2kg of a liquid for 20 seconds. If the temperature of the liquid rises by 5^oC, then the specific heat capacity of the liquid is

A. 2.0 x 10²Jkg^-1k^-1
B. 2.0 x 10²Jkg^-1
C. 4.0 x 10⁴Jkg^-1k^-1
D. 4.0 x 10⁴kg^-1
E. 8.4 x 10³Jkg^-1k^-1

Question 20:

• JAMB 1986

The specific latent heat of fusion of lead is the amount of heat required to

A. Melt lead at its melting point
B. Heat a unit mass of lead through 1^oC
C. Change the state of a unit mass of lead at its melting point
D. Change the state of a unit mass of lead at its boiling point