Thermal Properties Of Matter

The reason for the gap between the rail sections is to allow for expansion of the rail sections during hot weather. When the temperature rises, the metal rails expand, and if there were no gaps, the rails would buckle or warp. By providing gaps between the rail sections, the rails can expand without causing any damage or obstruction to the train's movement.

The rise in temperature can be calculated using the formula:

Rise in temperature = Energy supplied / (Mass * Specific heat capacity)

Plugging in the given values:

Rise in temperature = 2400 J / (2.0 kg * 800 J / (kg oC))

Rise in temperature = 2400 J / 1600 J / oC

Rise in temperature = 1.5 oC

When the temperature of a gas is raised, the average kinetic energy of its molecules increases. This increase in kinetic energy leads to an increase in the speed and movement of the gas molecules. As a result, the gas molecules collide with the walls of the container more frequently and with greater force. This increased collision force causes the gas to exert a greater pressure on the piston. In order to maintain the pressure equilibrium, the piston is pushed upwards, allowing the gas to expand and occupy a larger volume. Therefore, the correct statement is that the gas expands.

When the temperature rises, the gas inside the alarm expands. This causes the mercury pellet to move and complete the circuit, triggering the alarm.

When ice melts to become water, the force that must be overcome is the force between molecules. In the solid state, the water molecules are held together by intermolecular forces, specifically hydrogen bonding. When heat is applied, the kinetic energy of the molecules increases, causing them to vibrate and break free from the rigid structure of the ice. This requires overcoming the force of attraction between the molecules, allowing them to move more freely and form a liquid.

When the bimetallic strip is cooled, both the brass and invar contract. However, brass contracts more than invar. This difference in contraction causes the bimetallic strip to bend or change shape.

Heat capacity is defined as the quantity of heat required to raise the temperature of an object through 1 K. This means that it measures the amount of heat energy needed to increase the temperature of an object by 1 degree Kelvin. It is a property that depends on the mass and material of the object, and it is commonly used to describe the ability of a substance or object to store and transfer heat.

When a metal bar is heated, the molecules within the bar gain energy and start to move more rapidly. This increased movement causes the molecules to push against each other, resulting in an expansion of the bar. As a result, the distance between the molecules increases, making the bar longer.

Based on the information given, the ice cubes were taken from a deep-freeze, which means they were at a temperature of 0 °C. Therefore, the temperature that corresponds to 0 °C on the graph would be point C.

The energy required to change liquid water into water vapor, known as latent heat of vaporization, increases the average speed of the water molecules. This energy is used to overcome the intermolecular forces holding the water molecules together, allowing them to break free and move more rapidly as vapor.

When a tooth is heated, it expands. Therefore, it is important for fillings in teeth to be made from a material that also expands by the same amount as the tooth when heated. If the filling material expands more than the tooth, it could cause pressure and damage to the tooth. If it expands less than the tooth, there may be gaps between the filling and the tooth, allowing bacteria to enter and cause decay. If the filling material does not expand at all when heated, it may not fit properly in the tooth and could become loose or fall out.

The average electrical power used can be calculated using the formula: Power = Energy / Time. In this case, the energy can be calculated by multiplying the specific latent heat of steam (2250 J/g) by the mass of water (100 g), which gives us 225,000 J. The time is given as 300 seconds. Therefore, the average electrical power used is 225,000 J / 300 s = 750 W.

When the kettle is placed on the balance and the water inside continues to boil, the balance reading changes by 0.2 kg. This change in mass is due to the water vaporizing into steam. The specific latent heat of vaporization is the amount of energy required to convert 1 kg of a substance from liquid to gas at a constant temperature and pressure. In this case, the change in mass is 0.2 kg, and the kettle has a power of 2 kW. Given that the boiling process takes 5 minutes, we can calculate the energy transferred using the formula: Energy = Power x Time. Therefore, the specific latent heat of vaporization of water is 3,000,000 J/kg.

The specific latent heat of fusion of ice is given as 333 J/g. This means that it takes 333 J of heat energy to melt 1 gram of ice. The ice cube has a mass of 7.50 g, so it will require 333 J/g x 7.50 g = 2497.5 J of heat energy to melt completely.

The heat from the surroundings is reaching the ice cube at an average rate of 1.25 J/s. Therefore, it will take 2497.5 J / 1.25 J/s = 1998 s to melt all of the ice.

Since the question is asking for the time it takes for all of the ice to melt, the correct answer is 2000 s.

When the bimetallic strip made from brass and iron is heated, the brass expands more than the iron. As a result, the brass side of the strip will expand more than the iron side, causing the strip to bend towards the iron side. This bending shape is represented by option B in the given choices.

The bimetallic strip bends in the direction shown because metal A has a greater increase in length when heated compared to metal B. This causes one side of the strip to expand more than the other, resulting in the bending motion.

When a substance is heated strongly, the energy given to the substance causes the bonds holding the molecules together to break. This results in the molecules escaping from the liquid, causing a phase change from liquid to gas.

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