A piece of metal is heated until it becomes red-hot, it is then quickly transferred into a beaker containing boiling water. What effect will this have on the boiling water?
- A. the boiling water rises slightly
- B. the boiling point rises sharply
- C. the rate of vaporisation of the boiling water increases
- D. the boiling point first rises and then falls
- E. neither the boiling point nor the rate of vaporisation increases
A waterfall is 1260m high. Calculate the change in temperature of a quantity of water that falls from the top to the bottom of the waterfall. (Neglect heat losses to the surroundings, take g as 10m-2 and specific heat capacity of water as 4200Jkg-1K-1)
- A. 0.3oC
- B. 3.0oC
- C. 33.3oC
- D. 42.0oC
- E. 100.0oC
Dry oxygen is trapped by a pellet of mercury in a uniform capillary tube which is sealed at one end. The length of the column of oxygen at 27oC is 50cm. if the pressure of the oxygen is constant, at what temperature will the length be 60cm?
- A. 360.0oC
- B. 240.6oC
- C. 237.0oC
- D. 87.0oC
- E. 36oC
The inside of a vacuum flak is usually coated with silver to reduce heat loss by
- A. evaporation
- B. radiation
- C. conduction
- D. convention
- E. condensation
Air at temperature 527oC and pressure 30 atmospheres is admitted into the cylinder of an engine. Calculate the pressure of the gas when it has expanded to 5 times its volume and cooled to 127oC as it leaves the engine
- A. 1.5 atmospheres
- B. 2.5 atmospheres
- C. 3.0 atmospheres
- D. 12.8 atmospheres
- E. 15.0 atmospheres
If the cubic expansivity of brass between 27oC and 100oC is 5.7 x 10-5K-1, What is its linear expansivity?
- A. 2.85 x 10-5K-1
- B. 1.90 x 10-5K-1
- C. 1.86 x 10-5K-1
- D. 1.70 x 10-5K-1
- E. 1.63 x 10-5K-1
How much heat is emitted when a body of mass 200g cools from 37oC to 31oC? (specific heat capacity of the body = 0.4Jg-1K-1,)
- A. 4800J
- B. 1200J
- C. 480J
- D. 202J
- E. 80J
The average kinetic energy of the molecules of a perfect gas is directly proportional to the
- A. pressure exerted by the gas
- B. volume of the gas molecule
- C. kelvin temperature of the gas
- D. volume of the gas container
- E. celcius temperature of the gas
A piece of brass of mass 170kg has its temperature raised from 0oC to 30oC. Calculate its increase in volume, given the density of brass at 0oC as 8.5 x 103kgm3 and its cubic expansivity as 5.7 x 10-1k1
- A. 3.4 x 10-4m3
- B. 4.3 x 10-5m3
- C. 3.4 x 10-5m3
- D. 3.4 x 10-3m3
- E. 3.4 x 10-2m3
The lower and upper fixed points of a mecury-in-glass thermometer are marked Y and 180mm respectively. On a particular the mecury meniscus in the thermometer rises to 45mm. If the corresponding reading on a scale is 10o, calculate the value of Y.
- A. 4mm
- B. 18mm
- C. 30mm
- D. 135mm
- E. 450mm
An object is heated from 30ºC to 57ºC. The increases in its temperature on the Kelvin scale is
- A. 17k
- B. 27k
- C. 81k
- D. 246k
- E. 300k
a ball of mass 5.0kg hits a smooth vertical wall normally with a speed of 2m-1 and rebounds with the same speed. Determine the impulse experienced by the ball
- A. 20.0kgm-1
- B. 5.0kgm-1
- C. 1.3kgm-1
- D. 0.0kgm-1
- E. 10.0kgm-1
The earth is not a perfect sphere because its equatorial axis is longer than the polar axis. where on the earth’s surface would an object have its greatest weight?
- A. half way between the equator and the north pole
- B. near the equator
- C. half way between the equator and the south pole
- D. at either pole
- E. at the equator
An object is protected with a velocity of 100m-1 at an angle of 60o to the vertical. Calculate the time taken by the object to reach the highest point (Take g as 10ms-2
- A. 5.0s
- B. 8.7s
- C. 10.0s
- D. 17.3s
- E. 20.0s
a pilot records the atmospheric pressure outside his plane as 63cm of Hg while a ground observer records a reading of 75cm of Hg with his barometer. Assuming that the density of air is constant, calculate the height of the plane above the ground. (take the relative densities of air and mecury as 0.00136 and 13.6 respectively)
- A. 120m
- B. 138m
- C. 274m
- D. 1200m
- E. 120,000m
I the box is pulled from P to Q, which of the following expresses the velocity ratio of the inclined plane?
- A. PR/PQ
- B. OR/PQ
- C. OR/PR
- D. PQ/PR
- E. PQ/QR
If \(\theta\) is equal to \(\alpha\) at the time the box is just about to slide down the plank, the coefficient of static friction between the plank and box is
- A. sin\(\alpha\)
- B. cos\(\alpha\)
- C. tan\(\alpha\)
- D. sec\(\alpha\)
- E. cot\(\alpha\)
As the end Q of the plank is raised, the component of W, normal to plank, will
- A. increase
- B. decrease
- C. remain the same
- D. be slightly greater than W
- E. be independent of w
A rectangular block of wood floats in water with two-thirds of its volume immersed. When placed in another liquid, it floats with half of its volume immersed. Calculate the relative density of the liquid
- A. 1.43
- B. 1.33
- C. 1.00
- D. 0.83
- E. 0.75
The term torque means
- A. the moment
- B. the resultant of several forces acting on a body in equilibrum
- C. two equal and oposite forces whose lines of action do not coincide
- D. two coplaner forces at right angles to each other
- E. the equilibrant of two concurrent forces
A piece of stone attached to one end pf string is whirled round in a horizontal circle. When the string is suddenly cut, the stone will
- A. move towards te centre of the circle
- B. stop moving immediately
- C. move along a circular path of smaller radius
- D. fly off in a direction tangential to the circular path
- E. acquire greater centripetal force