Question 626:

• JAMB 1991

The spiral spring of a spring balance is 25.0cm long when 5N hangs on it and 30cm long, when the weight is 10N. What is the length of the spring if the weight is 3N assuming Hooke's law is obeyed?

A. 15.0cm
B. 17.0cm
C. 20.0cm
D. 23.0cm

Question 627:

• JAMB 1991

The mass of a stone is 15.0g when completely immersed in water and 10.0g when completely immersed in a liquid of relative density 2.0. The mass of the stone in air is

A. 5.0g
B. 12.0g
C. 20.0g
D. 25.0g

Question 628:

• JAMB 1991

A pilot records the atmospheric pressure outside its plane as 63cm of Hg while a ground observer records a reading of 75cm of Hg for the atmospheric pressure on the ground. Assuming that the density of the atmosphere is constant, calculate the height of the plane above the ground. (Relative density of Hg = 13.0 and that of air = 0.00013)

A. 1200m
B. 6300m
C. 7500m
D. 13800m

Question 629:

• JAMB 1991

In which of the following is surface tension important?

A. The floating of a ship in water
B. The floating of a dry needle in water
C. The floating of a baloon in air
D. The diffusion of sugar solution across a membrane

Question 630:

• JAMB 1991

A thermometer with an arbitrary scale S, of equal division registers -30^oS at the ice point and +90^oS at the steam point. Calculate the Celsius temperature corresponding to 60^oS

A. 25.0^oC
B. 50.0^oC
C. 66.7^oC
D. 75.0^oC