State two ways in which mercury based thermometer can be modified to read very small temperature changes. (Answered)
Explain how a greenhouse gets warm. (Answered)
Figure 6 shows a glass tube with water fitted with two identical thermometers A and B. it is heated as shown.
State with reason which one of the two thermometers shows a higher temperature. (Answered)
Figure 4 shows a source of heat placed at equal distances from two identical flasks X and Y containing air. The surface of X is painted black while Y is clear.
X and Y are linked by a U-tube filled with water whose level S and T are initially the same; it is later observed that S falls while T rises. Explain this observation. (Answered)
Figure 3 shows a piece of wood fitted into a copper pipe and a piece of paper wrapped tightly around the junction.
It is observed that when a flame is applied around a paper at the junction, the
side of the paper around the wood burns first. Explain this observation. (Answered)
(a) Figure 11 shows how underground room was ventilated. It had two vents, one at A and the other at B. A fire was lit at point C. Explain what happened to the ventilation when fire was lit.
(b) Explain how a vacuum flask minimizes loss of heat through radiation. (Answered)
Figure 4 shows identical beakers P and Q full of water at #90^0C#. Two similar cold wet clothes are wrapped, one around the top of P and the other around the bottom Q.
State with a reason the beaker in which the water cools faster. (Answered)
A paper windmill in a horizontal axis was placed above a candle as shown in figure 2. When the candle was lit the paper windmill begun to rotate. Explain this observation. (Answered)
Two identical empty metal containers P and Q are placed over identical Bunsen burners and the burners lit. P is dull black while Q is shiny bright. After each container attains a temperature of #100^0C# the burners are turned off. Two identical test tubes containing water are suspended in each container without touching the sides as shown in figure 3.
(Answered)
Two identical empty metal containers P and Q are placed over identical Bunsen burners and the burners lit. P is dull black while Q is shiny bright. After each container attains a temperature of #100^0C# the burners are turned off. Two identical test tubes containing water are suspended in each container
without touching the sides as shown in figure 3.
Explain why container Q may become hot faster (Answered)
Figure 3 shows a hot water bath with metal rods inserted through one of its sides. Some wax is fixed at the end of each rod.
Besides the length of the rods that is kept constant, what else should be kept constant when comparing the property for the different metal rods? (Answered)
Figure 3 shows a hot water bath with metal rods inserted through one of its sides. Some wax is fixed at the end of each rod.
What property of metals could be tested using this set up. (Answered)
Figure 4 shows two identical balloons A and B. The balloons were filled with equal amounts of the same type of gas. The balloons are suspended at a distances x1 and x2 from a metal cube filled with boiling water and placed on an insulating material.
State the mode by which heat travels from the cube to the balloons. (Answered)
In a vacuum flask the walls enclosing the vacuum are silvered on the inside. State the reason for this. (Answered)
Two identical aluminium rods are shown in figure 4. One rests on metal block and other on a wooden block. The protruding ends are heated on a Bunsen burner as shown.
State with reason which bar the wax likely to melt sooner. (Answered)
When a Bunsen burner is lit below wire gauze, it is noted that the flame initially burns below the gauze as shown in figure 5(i). After some time, the flame burns below as well as above the gauze as shown in figure 5(ii)
Explain the observation. (Answered)
An electric heater is placed at equal distances from two similar metal cans A and B filled with water at room temperature. The outer surface of can A is shiny while that of B is dull black. State with reasons which can will be at a higher temperature after the heater is switched on for some time. (Answered)
Figure 1 below shows a cross –section of a vacuum flask.
(i) Name the parts labeled A and B
(ii) Explain how the heat losses are minimized when hot liquid is poured into the flask.
(iii) Boiling water is poured into two identical vacuum flasks A and B. flask A is partially filled while B is completely filled. Both
are closed tightly. State with reasons the flask in which the water is likely to hav (Answered)
Figure 12 shows two identical containers A and B into which a copper rod is fitted. The containers are well lagged.
The liquids in the containers were initially at the same temperature. If the heat is applied continuously at the position shown, state with a reason the container through which the loss of heat is likely to be higher. (Answered)
A wooden bench and a metal bench are both left in the sun for a long time. Explain why the metal bench feels hotter to touch. (Answered)
In fig 4 one end of a metal rod is placed in steam and the other end in melting ice. The length of the rod in between is lagged.
State two factors that determine the rate at which ice melts. (Answered)
Give a reason why heat transfer by radiation is faster than heat transfer by conduction. (Answered)
State two variables that must be controlled in an experiment for comparing the thermal conductivities of different metal rods of the same diameter (Answered)
In the set up shown in figure 3, water near the top of the boiling tube boils while at the bottom it remains cold
Give a reason for the observation. (Answered)
State two ways in which xylem vessels are adapted to their function. (Answered)
The diagram below represents a transverse section of a young stem.
(b) State the functions of the parts labeled C, D, and E.
(c) List three differences between the section shown above and one that would be obtained from the root of the same plant. (Answered)
Figure 6 shows two solids W and X made of the same material and immersed in water.
(i) State with a reason one of the containers experiences a greater upthrust. (Answered)
A balloon is filled with a gas which is lighter than air. It is observed to rise in air up to a certain height. State a reason why the balloon stops rising. (Answered)
A ship made of steel is observed to float on water yet the density of steel is approximately eight times that of water. Explain this observation. (Answered)
State the condition necessary for a body to float in a fluid (Answered)
The system in figure 8 is in equilibrium
When the temperature of the water is raised the system is observed to tilt to the right. State the reason for this observation. (Answered)
The system in figure 8 is in equilibrium When the temperature of the water is raised the system is observed to tilt to the right. State the reason for this observation. (Answered)
Figure 14 shows a cork floating on water and held to the bottom of the beaker by a thin thread.
(i) Name the forces acting on the cork
(ii) Describe how each of the forces mentioned in (i) above changes when water added into the beaker until it fills up. (Answered)
Figure 13 shows a simple hydrometer
(i) State the purpose of the lead shots in the glass bulb
(ii) How would the hydrometer be made more sensitive?
iii) Describe how the hydrometer is calibrated to measure relative density.
(Answered)
State the law of floatation (Answered)
State Archimedes principle (Answered)
The uniform bar in Figure 7 is pivoted at its midpoint. It is in equilibrium under the action of two identical balloons filled with equal volumes of different light gases at the same temperature.
Explain why the bar may not remain in equilibrium if the temperature of the surrounding changes. (Answered)
The system in Figure 2 is in equilibrium at room temperature.
The system is taken outside where the temperature is 100c higher for some time.
Explain why this tips to the right immediately it is returned to the room. (Answered)
When a piece of metal is placed on water, it sinks. But when the same piece of metal is placed on a block of wood, both are found to float. Explain this observation. (Answered)
Figure 2 shows a uniform bar in equilibrium.
When water is added into the beakers A and B until the weights are submerged, it is observed that the bar
tips towards B. Explain the observation. (Answered)
(i) You are provided with the following :
-an overflow can
-a spring balance
-water
-a beaker
-a metal block
-a string
Describe an experiment to verify Archimedes principle (Answered)
Explain the following observation: ice cubes float on water and solid benzene sinks in liquid benzene (Answered)
A solid copper sphere will sink in water while a hollow copper sphere of the same mass may float. Explain this observation (Answered)
State one function of the court of justice of the Common Market for East and Southern Africa (COMESA). (Answered)
Give two functions of the East African Legislative assembly of the East African
Community, (2001). (Answered)
State five functions of the commission of the African Union. (Answered)
Identify five contributions made by Kwame Nkrumah of Ghana in promoting Pan
Africanism. (Answered)
Name any financial institution established by the African union. (Answered)
State three objectives for the formation of the Common Market for Eastern and Southern Africa (COMESA). (Answered)
Identify three duties performed by the secretary general of the new East African Community established in 2001. (Answered)