A body of volume 0.046m3 is immersed in liquid of density 980 km-3 with ¾ of its volume submerged . Calculate the upthrust on the body . [ g = 10 ms -2 ]
Electrical energy is measured in
A stone of mass 0.50kg is dropped from a height of 12 m . Calculate its maximum kinetic energy. [ g= 10ms-2 ]
A machine of efficiency 80% is used to lift a box. If the effort applied by the machine is twice the weight of the box, calculate the velocity ratio of the ratio of the machine.
A faulty thermometer registers 102.5oC at 100oC. If the thermometer has no zero error, what will it register at 55oC?
As a bicycle tyre was being pumped up, it was noticed that contrary to Boyle's law the volume increased as the pressure increased. The best explanation of this is that Boyle's law is only true for
a fixed mass of gas
a mixture of gases
a gas at variable temperature
It takes 4 minutes to boil a quantity of water using an electrical heating coil. How long will it take to boil the same quality of water using the same heating coil if the current is doubled? [ Neglect any external heat losses]
When table salt is added to ice, the melting point of the ice
is first raised, then lowered
Which of the following factors affect the rate of evaporation of a liquid?
I. Exposed surface area
II. Temperature of the surroundings
III. Thermal capacity of the liquid
IV. Relative humility of the surroundings
II and III only
II, III and IV only
I , III and IV only
I, II and IV only
Which of the following instruments is used to measure relative humidity?
A rectangular block of dimensions 2.0mx1.0mx0.5m weighs 200 N. Calculate the maximum pressure exerted by the block on a horizontal floor
Which of the following devices converts heat energy to electrical energy?
An object of mass 0.25 kg moves at a height h above the ground with a speed of 4ms-1 . If its electrical energy at height is J, determine the value of h. [ g= 10ms-1]
which of the following equations for the efficiency of a machine is correct?
Efficiency = Velocity Ratio
Mechanical Advantage x 100%
Efficiency = Input
Output X 100%
Efficiency = Load distance
Effort distance X 100%
Efficiency = Mechanical Advantage
Velocity Ratio X 100%
The design of the thermostat of an electric iron is based on the
emission of electrons from metals when heated
increase in size of metals when heated
increase in the density of metals when heated
change in the mass of metals when heated
A metal rod of length 50cm is heated from 40oC to 80oC. if the linear expansivity of the material is α
The cubic expansivity of a certain gas at constant pressure is 1/273 K-1. If a given mass of the gas is held at constant pressure and its volume of the gas at 273oc.
Water of mass 1.5 kg ids heated from 30oC to 80oC using an electric kettle which is rated 5A, 239V. Calculate the time taken to reach the final temperature.
[Specific heat capacity of water = 4200 Jkg-1 K -1]
The working principle of a pressure cooker is based on on the
increase in the volume steam inside it
complete trapping of heat inside it
increase in the pressure of pot
decrease in the pressure of pot
It takes a shorter time for a liquid to boil at the top of a mountain than at the base because at the top, the
temperature is higher
pressure is lower
humidity is higher
temperature is constant
Mechanical energy can be either
Kinetic or electric
chemical or potential
potential or kinetic
electric or heat
The ice and stream points on a mercury-in-glass thermometer are 10cm and 30cm respectively. Calculate the temperature in degree celcius, when the mercury meniscus is at the 14 cm mark
Which of the following surfaces will radiates heat energy best?
Which of the following statements distinguishes thermal conduction from convection?
I. Conduction requires a material medium while convection does not
I and II only
II and III only
I and III only
I , II and III
A cube made of a metal of linear expansivty α is heated through a temperature θ. If the initial volume of the cube is Vo, the correct expression for the increase in volume of the cube is
1/3 α Voθ
1/2 α Voθ
2 α Voθ
3 α Voθ
A relative density bottle of volume 50cm3 is completely filled with a liquid at 30oC. It s then heated to 80oC such that 0.75cm3 of the liquid is expelled. Calculate the apparent cubic expansivity of the liquid .
A body of mass 200g and specific heat capacity 0.4 Jg-1K-1 cools from 37oC to 31oC. Calculate the quantity of heat released by the body
According to the kinetic theory of gases, which of the following properties of a gas an be affected by the collision of the gas molecules with the walls of its container ?
The pressure of a fixed mass of a idea gas at 27oC is 3 Pa. The gas is heated at a constant volume until its pressure is 5 Pa . Determine the new temperature of the gas
Which of the following sources of energy is renewable?
Which of the following statements about the mouth piece of a telephone is correct? It converts sound energy into
The potential energy string of force constant k which has been extended by x meters is expressed as
The engine of train produces a force of 3000N when moving at 30 ms-1. Calculate the power of the engine.
1.00 x 102W
3.00 X 104 W
9.00 X 104 W
3.00 x 105 W
A block and tackle system has six pulleys. A force of 50 N applied to it lifts a load of weight W. If the efficiency of the system is 40%, calculate W
The sagging of overhead electrical cables is the consequence of
The sliver surface in vacuum flask reduces heat loss due to
How long will it take gto heat 3kg of water from 28oC to 88oC in an electric kettle taking 6A from a 220V supply? [ specific heat capacity of water = 4180 J kg-1K-1 ]
The amount of energy required to change a kilogram of ice block into water without a change in temperature is
heat capacity of ice
specific heat capacity
specific latent heat of vapourization of ice
specific latent heat of fussion of ice
A quantity of stream at 100oC condenses to water at the same temperature by releasing 6.9X104J of energy. Calculate the mass of the condensed steam. [specific latent heat of vapourisation of water = 2.3 x 106 J kg-1]
3.0 X 10-1 kg
3.0 X 10-2kg
3.0 X 10-3 kg
3.0 X 10-4 kg
The temperature of liquid fall after some of it has evaporated because
the liquid left is smaller in volume and the breeze easily cools it
the more energenic molecules have escaped into the atmosphere
the liquid left has less latent heat
after evaporation impurities are left behind
Which of the following simple machines is a second class level?
Which of the following quantities has the same unit as energy?
Which of the following sources of energy is renewable?
The lower and upper fixed points of a thermometer are 30mm and 180mm respectively. Calculate the temperaturte in degrees celsius when the thermometer reads 45mm.
A body of mass m has a specific heat capacity s and a heat capacity c. If the temperature of the body changes by θo C, which of the following equations is correct?
ms0 = mc-1
ms = sθ
ms = cθ
An immersion heater rated 400W, 220V is used to heat a liquid of mass 0.5kg . If the temperature of the liquid increases uniformly at the rate of 2.50C per second, calculate the specific heat capacity of the liquid. [Assume no heat is lost ]
Water falls through a height of 50cm. Determine the temperature rise of water at the bottom of the fall. [Neglect energy losses. Specific heat capacity of water = 4200Jkg-1 K-1, g= 10ms-2 ]
The energy required to change a solid to liquid at constant temperature is called
specific heat capacity
latent heat of fussion
latent heat of vapourisation
Which of the following statements about boiling and evaporation at atmosphere pressure is correct?
Evaporation and boiling of water take place at 100oC
Evaporation of water takes place at a temperature greater than 100oC, while boiling of water takes place at 100oC
Evaporation of water takes place at 100oC wehile boiling of water takes place at a higher temperature
Boiling takes place at 100oC while evaporation may take place at temperatures lower than 100oC
Which of the following statements is correct?
the density of a liquid decreases when it expands
the densities of liquid increase when the liquid are heated
the real expansivity of a liquid is less its apparent expansivity
a liquid changes to solid when heated to a sufficiency high temperature
The pressure exerted by a given mass of gas in a container
decreases if the container is heated
increases if the molecules of the gas move faster.
increases if the volume of the container is doubled
decreases as the kinetic energy of the gas molecules increases
A driver is 5.2m below the surface of water of density 1000kgm-3 . If the atmospheric pressure is 1.02 x 105 Pa, calculate the pressure on the driver . [ g= 10 mS-2 ]
6.20 x 104 Pa
1.02 x 105 Pa
1.54 x 105 Pa
5.20 x 105 Pa
Calculate the change in volume when 90 g of ice is completely melted.
[ density of water = 1 g cm3, density of ice=0.9 g cm3]
A machine of velocity ratio 5 is used in lifting a load with an effort of 500N. If the machine is 80% efficient, determine the magnitude of the load.
When compared with water, mercury is preferred as a thermometric liquid because it
has higher density
has a lower specific heat capacity
exhibits anomalous thermal expansion
contains molecules which have very strong adhesive forces
Which of the following values on the absolute scale of temperature is the ice point?
On a cold day, a concrete floor feels colder to the bare foot than a mat on the same floor because the
mat is a better conductor of heat than the foot
mat loses heat to the bare foot at a faster rate
mat is a better conductor of heat than the floor
concreate floor is a better conductor of heat than the mat
When a metal ball is heated through 30oC, its volume becomes 1.00180ms-3 . If the linear expansivity of the material of the ball is 2.0 x 10-5 K-1 , calculate its original volume.
A faulty barometer reads 72.6cm Hg when the atmospheric pressure is 75.0 cmHg. Calculate the atmospheric pressure when this barometer reads 72.0 cm Hg.
On the basis of the kinetic theory, an increase in the temperature of a fixed volume of an ideal gas causes
an increase in the number of the gas molecules
a decrease in the density of the gas
an increase in the average speed of the gas molecules
a decrease in the pressure exerted by the gas