8TH GRADE PRACTICE
Physics Problems: Thermal phenomena, Grade 8
MCT, temperature, internal energy and heat transfer.
Here the conditions and analysis of the solution can be read without an account. In the simulator, you need to collect the same analyzes yourself: “Given,” formulas, order of steps and answer.
Problem statements
The answer options are there to check against, and the walkthrough opens under each problem.
Problem #1
MCT and surface phenomenaEvaluate the statement: The rise or fall of liquid in a thin tube is due to surface forces and wetting of the walls.
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The narrower the wetted capillary, the more noticeable the rise; the phenomenon helps water move through the pores of soil and plants.
Answer
Problem #2
MCT and surface phenomenaEvaluate the statement: The concept of “Wetting and non-wetting” means: Substances are made up of particles, the particles are constantly moving and interact by attraction and repulsion.
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Water spreads over clean glass, but collects in drops on the wax surface; the shape of the meniscus reflects the relationship of forces.
Answer
Problem #3
Surface phenomenaWater wets clean glass. How will the height of its rise change if the capillary is replaced with a narrower one?
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Answer
Problem #4
Temperature and internal energyEvaluate the statement: The state of contacting bodies in which their temperatures are equal and directed heat exchange ceases.
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The thermometer displays the temperature correctly after establishing thermal equilibrium with the body being measured.
Answer
Problem #5
Temperature and internal energyEvaluate the statement: the concept of “Temperature scales” means: The sum of the kinetic energy of the chaotic movement of particles and the potential energy of their interaction.
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Zero degrees Celsius corresponds to approximately 273.15 kelvin, and absolute temperature is never negative.
Answer
Problem #6
TemperatureThe air temperature is 27 °C. Find the absolute temperature, rounding the result to the nearest whole kelvin.
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Answer
Problem #7
Thermal conduction, convection and radiationEvaluate the statement: Transfer of internal energy upon contact of particles without transfer of matter as a whole.
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Metals usually conduct heat well, and air and porous materials are used as heat insulators.
Answer
Problem #8
Thermal conduction, convection and radiationEvaluate the statement: The concept “Convection” means: The transfer of energy by electromagnetic waves that does not require matter between bodies.
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Warm layers tend to rise and cooler layers to sink; Convection is impossible in solids.
Answer
Problem #9
Heat transferWhich combination of solutions most strongly reduces all three methods of heat transfer in a thermos?
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Answer
Problem #10
Amount of heat and heat balanceEvaluate the statement: Energy transferred to or given up by a body during the process of heat transfer.
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When heated without a phase transition, the amount of heat depends on the mass, heat capacity of the substance and temperature change.
Answer
Problem #11
Amount of heat and heat balanceEvaluate the statement: the concept “Calorimeter and heat balance” means: Complete combustion of fuel releases energy proportional to the mass and specific heat of combustion.
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To determine specific heat capacity, mass and temperature are measured, then a balance equation with a single sign is drawn up.
Answer
Problem #12
HeatTwo kilograms of water were heated by 10 K. The specific heat capacity of water is 4200 J/(kg K). How much heat did the water receive?
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The theory behind these problems
Work through the topic if a problem will not give in.
Formulas by topic
Look up symbols and units of measurement in the reference.