Category: heat A-level

Describe Searle’s method of determining the thermal conductivity of a good conductor of heat.

09/18/2021 0

Specimen bar AB of mean diameter, d, is heated by steam at end A and cooled by water at end B as shown above The ... Read More

Explain how cooking at a pressure of 76cm of mercury and temperature of 1000C may be achieved on top of high mountains. 

09/18/2021 0

Cooking pans are fitted with lids that possess safety valves that open when the pressure exceeds 76cmmmHg. During cooking the vapour pressure inside the cooking ... Read More

Describe an experiment to show that a liquid boils only when its saturated vapor pressure is equal to external pressure (05marks)

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Experiment to show that a liquid boils off when its saturated vapour pressure equals the external pressure Air is trapped in the closed limb of ... Read More

Explain the significance of latent heat in regulation of body temperature (03marks)

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Explain the significance of latent heat in regulation of body temperature (03marks) On a hot day, the body sweats. Evaporation occurs at the surface of ... Read More

State the laws of black body radiation (02marks)

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State the laws of black body radiation (02marks) The wavelength λm at which maximum energy is radiated for temperature, T ia such that λmT = ... Read More

Explain in terms of specific heat capacity why water is used in a car radiator other than any other liquid. (02mark)

09/18/2021 0

Explain in terms of specific heat capacity why water is used in a car radiator other than any other liquid. (02mark) Water has very high ... Read More

With the aid of a labelled diagram, describe how the room temperature can be measured using uncalibrated resistance thermometer. (06marks)

09/18/2021 0

With the aid of a labelled diagram, describe how the room temperature can be measured using uncalibrated resistance thermometer. (06marks) Place the resistance thermometer in ... Read More

State Prevost’s theory of heat exchange. (01mark)

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State Prevost’s theory of heat exchange. (01mark) A body at constant temperature is in of dynamic equilibrium with its surroundings. The rate of radiation being ... Read More

Explain why the specific latent heat of fusion and specific latent heat of vaporization of a substance at the same pressure are different. (04marks)

09/18/2021 0

Explain why the specific latent heat of fusion and specific latent heat of vaporization of a substance at the same pressure are different. (04marks) Change ... Read More

Explain why the temperature of a liquid does not change when the liquid is boiling? (02marks)

09/18/2021 0

Explain why the temperature of a liquid does not change when the liquid is boiling? (02marks) When the liquid boils, there is change in a ... Read More

Why is the distinction between specific heat capacity at constant pressure and that at constant volume important for gases, but less important for solids and liquids? (04marks)

09/18/2021 0

Why is the distinction between specific heat capacity at constant pressure and that at constant volume important for gases, but less important for solids and ... Read More

Define the term specific heat capacity and internal energy and state their units.

09/18/2021 0

Define the term specific heat capacity and internal energy and state their units. (03marks)   Specific heat capacity is the amount of heat required to ... Read More

Explain the greenhouse effect and how it is related to global warming. (04marks)

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Explain the greenhouse effect and how it is related to global warming. (04marks) Short wavelength radiation from the sun passes through glass of green house. ... Read More

State one advantage and one disadvantage of the resistance thermometer

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State one advantage and one disadvantage of the resistance thermometer. (01mark) Advantage - measures a wide range of temperatures - very accurate   Disadvantages unsuitable ... Read More

Describe an experiment to verify Boyles’ law

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Describe an experiment to verify Boyles’ law   air in the closed limb of a U-tube barometer as shown above mercury is poured to a ... Read More

Heat Physic (A-level)

09/17/2021 0

Heat This is a form of energy which that rises the temperature of substances. Means of heat transfer Conduction Conduction is the process of heat ... Read More

Explain  disadvantages of using the discharge tube in producing cathode rays.

09/04/2021 0

Explain  disadvantages of using the discharge tube in producing cathode rays. a discharge tube is operated at very high voltage which is not safe to ... Read More

Give one characteristic property of infrared radiation.

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Give one characteristic property of infrared radiation. Causes sensation of warmth (increases body temperature. Please Subscribe to promote this website. Subscription is free Share with ... Read More

Two thermometers are used to measure the temperature of a body. Explain why the temperatures may be different. 

09/04/2021 0

Two thermometers are used to measure the temperature of a body. Explain why the temperatures may be different. Because thermometric properties vary differently with temperature ... Read More

With the aid of labelled diagram, describe an experiment to measure the specific latent heat of vaporization of a liquid using an electrical method. 

09/04/2021 0

With the aid of labelled diagram, describe an experiment to measure the specific latent heat of vaporization of a liquid using an electrical method. Put ... Read More

With the aid of labelled diagram, describe an experiment to measure the specific latent heat of vaporization of a liquid using an electrical method.

09/04/2021 0

With the aid of labelled diagram, describe an experiment to measure the specific latent heat of vaporization of a liquid using an electrical method. Put ... Read More

State Stefan’s law. 

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State Stefan’s law. Stefan’s law states that the total power radiated by a black body per unit surface area is proportional to the fourth power ... Read More

Describe an experiment to compare the energy radiated by two surfaces at different temperatures

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Describe an experiment to compare the energy radiated by two surfaces at different temperatures A metal cube whose sides have a variety of finishes; dull ... Read More

Explain with the aid of a diagram how black body can be approximated. 

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Explain with the aid of a diagram how black body can be approximated. When radiation enters a black container through a hole, it undergoes multiple ... Read More

Sketch graphs of pressure against temperature for an ideal gas and for saturated water vapour originally at 00C

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Sketch graphs of pressure against temperature for an ideal gas and for saturated water vapour originally at 00C Please Subscribe to promote this website. Subscription ... Read More

Explain how a welder can protect the eyes from damage.

09/04/2021 0

Explain how a welder can protect the eyes from damage. A welder puts on dark shades that absorb ultraviolet light which damages the eyes.   ... Read More

Explain clearly the steps taken to determine the cooling correction when measuring the specific heat capacity of a poor conductor by the method of mixtures.

09/04/2021 0

Explain clearly the steps taken to determine the cooling correction when measuring the specific heat capacity of a poor conductor by the method of mixtures. ... Read More

Describe, with the aid of a diagram an experiment to determine specific heat of vaporization of steam using the method of mixtures.

09/04/2021 0

Describe, with the aid of a diagram an experiment to determine specific heat of vaporization of steam using the method of mixtures. The initial temperature ... Read More

With the id of diagram explain how a bolometer is used to detect thermal radiation.

09/04/2021 0

With the id of diagram explain how a bolometer is used to detect thermal radiation. The bolometer strip is connected to Wheatstone bridge circuit above. ... Read More

State Prevost’s theory of heat exchanges

09/04/2021 0

State Prevost’s theory of heat exchanges When a body is in thermal equilibrium with its surrounding, its rate of emission of radiation to surrounding is ... Read More

Sketch and explain graphs of intensity versus wavelength for three different temperatures of a black body. 

09/04/2021 0

Sketch and explain graphs of intensity versus wavelength for three different temperatures of a black body. As temperature increases, the intensity increases. The intensity of ... Read More

Explain briefly the effect of altitude on the boiling point of a liquid

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Explain briefly the effect of altitude on the boiling point of a liquid A liquid boils when its saturated vapour pressure is equal to the ... Read More

What is meant by saturated  vapour?

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What is meant by saturated  vapour? A saturated vapour is a vapour in dynamic equilibrium with its own liquid. Please Subscribe to promote this website. ... Read More

Explain why adiabatic expansion of a gas causes cooling 

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Explain why adiabatic expansion of a gas causes cooling During an adiabatic expansion of a gas, no heat is supplied to the gas. Molecules strike ... Read More

What is meant by isothermal process and adiabatic process. 

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What is meant by isothermal process and adiabatic process. Isothermal process is the expansion or compression of a gas at constant temperature. Adiabatic process is ... Read More

Explain why there is no change in temperature when a substance is melting 

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Explain why there is no change in temperature when a substance is melting Supply of heat to a melting solid reduces the forces of attraction ... Read More

Explain why there is no change in temperature when a substance is melting 

09/04/2021 0

Explain why there is no change in temperature when a substance is melting Supply of heat to a melting solid reduces the forces of attraction ... Read More

Define specific latent het of fusion 

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Define specific latent het of fusion Specific latent het of fusion is the amount of heat required to change 1kg mass of a substance from ... Read More

Explain the greenhouse effect and how it leads to rise of the earth temperature

09/04/2021 0

Explain the greenhouse effect and how it leads to rise of the earth temperature. The short wavelength radiation from the sun penetrates the atmosphere and ... Read More

Describe briefly an experiment to verify Newton’s law of cooling. 

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Describe briefly an experiment to verify Newton’s law of cooling. Hot water in a calorimeter is placed near an open window. The temperature of the ... Read More

State Newton’s law of cooling 

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State Newton’s law of cooling It state that the rate of loss of heat is proportional to the excess temperature between the body and the ... Read More

Explain the mechanism of heat transfer by convention. 

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Explain the mechanism of heat transfer by convention. When a fluid is heated from underneath, it expands and becomes less dense than fluid above. The ... Read More

Sketch a pressure versus volume curve for a real gas undergoing compression

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Sketch a pressure versus volume curve for a real gas undergoing compression Above the critical temperature, a real gas behaves ideally. Below the critical temperature ... Read More

Explain how the pressure of a fixed mass of a gas can be increased at constant volume

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Explain how the pressure of a fixed mass of a gas can be increased at constant volume By heating the gas, the molecules gain more ... Read More

Explain how the pressure of a fixed mass of a gas can be increased at a constant temperature 

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Explain how the pressure of a fixed mass of a gas can be increased at a constant temperature By reducing the volume occupied by a ... Read More

What is meant by boiling point?

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What is meant by boiling point? The boiling point of a liquid is the temperature at which its saturated vapour pressure equals the external pressure. ... Read More

Describe with the aid of a diagram the operation of an optical pyrometer 

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Describe with the aid of a diagram the operation of an optical pyrometer the filament is focused on the eye piece and the objective lens ... Read More

State disadvantages of a mercury in glass thermometer.

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State disadvantages of a mercury in glass thermometer. it is not very sensitive it cannot measure rapidly changing temperature it is delicate, i.e. it breaks ... Read More

Give characteristic of a good thermometric property.

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Give characteristic of a good thermometric property. should vary linearly with change in in temperature Should vary continuously with temperature Should be sensitive to temperature ... Read More

Describe an experiment to determine thermal conductivity of glass.

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Describe an experiment to determine thermal conductivity of glass. Glass s cut in form of a thin disc of cross section area, A and thickness, ... Read More

Give  examples of a black body. 

09/04/2021 0

Give  examples of a black body. The sun Star Black hole (remnants of a star after it has used up all its energy] An almost ... Read More

Explain why heating system based on the circulation of steam are more efficient than those based on circulation of boiling water. 

09/04/2021 0

Explain why heating system based on the circulation of steam are more efficient than those based on circulation of boiling water. A given mass of ... Read More

Explain the occurrence of land and sea breezes.

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Explain the occurrence of land and sea breezes. During day, the land is heated to a high temperature than the sea. Hot air expands and ... Read More

Explain why mercury conducts heat better than water.

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Explain why mercury conducts heat better than water. Mercury has free electrons capable of transferring energy without any part of mercury moving. Mercury atoms are ... Read More

What is meant by conduction of heat? 

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What is meant by conduction of heat? Conduction of heat is a process of heat transfer by which heat floe from a hotter region of ... Read More

State two disadvantages of the continuous flow method

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State two disadvantages of the continuous flow method larger volumes of liquid required not suitable for volatile liquids.   Please Subscribe to promote this website. ... Read More

State advantages of the continuous flow method over the method of mixtures. during the determination of specific heat 

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State advantages of the continuous flow method over the method of mixtures. during the determination of specific heat No cooling correction is required Heat capacity ... Read More

Describe with the aid of a diagram, an experiment to determine the specific heat capacity of a liquid using the continuous flow method.

09/04/2021 0

Describe with the aid of a diagram, an experiment to determine the specific heat capacity of a liquid using the continuous flow method.   A ... Read More

Describe briefly how to determine the lower and upper fixed points for an uncalibrated liquid-in-glass thermometer.

09/04/2021 0

Describe briefly how to determine the lower and upper fixed points for an uncalibrated liquid-in-glass thermometer. the bulb of the thermometer is immersed in pure ... Read More

State examples of commonly used thermometric properties. 

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State examples of commonly used thermometric properties. e.m.f of thermocouple pressure of a gas volume of mercury in glass resistance of platinum wire Please Subscribe ... Read More