Can You Answer These Questions On 8th Grade Physics?

1.

What are the units of specific heat capacity?

A.

J/kg^oC
B.

Jkg^oC
C.

J^-1kg/^oC
D.

W/kg/^oC

Correct Answer
A. J/kg^oC

Explanation
The units of specific heat capacity are J/kgoC. This represents the amount of heat energy required to raise the temperature of one kilogram of a substance by one degree Celsius. The unit "J" stands for joules, which is the standard unit of energy, "kg" represents kilograms, and "oC" represents degrees Celsius.

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2.

As well as the specific heat capacity, what else affects the amount of thermal energy a material can store?

A.

Nothing - it's just the specific heat capacity that matters
B.

The temperature change
C.

The mass
D.

Both temperature change and mass

Correct Answer
D. Both temperature change and mass

Explanation
The amount of thermal energy a material can store is influenced by both the temperature change and the mass. The temperature change determines how much the material's internal energy will increase or decrease, while the mass determines the amount of material available to store thermal energy. Therefore, both factors are important in determining the amount of thermal energy a material can store.

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3.

What symbol is used to represent the specific heat capacity of a material?

A.

A
B.

B
C.

C
D.

Shc

Correct Answer
C. C

Explanation
The symbol used to represent the specific heat capacity of a material is "c".

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4.

A block of copper was heated from 18^oC to 33^oC using 35 thousand joules of energy. The specific heat capacity of copper is 385 J/kg^oC. What was the mass of the block of copper?

A.

6.06 kg
B.

0.385 kg
C.

385 kg
D.

It can't be worked out without more information

Correct Answer
A. 6.06 kg

Explanation
To find the mass of the copper block, we use the formula for heat transfer, which relates the heat transferred to the mass, specific heat capacity, and change in temperature of the material. Given the heat transferred (35,000 J), specific heat capacity of copper (385 J/kg°C), and temperature change (15°C), we substitute these values into the formula to find the mass. This calculation yields a mass of approximately 6.06 kilograms for the copper block.

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5.

In a laboratory experiment, a group of students used a copper block with a hole drilled in for a thermometer and a second hole in for the heater. Which of the following is not required to calculate the specific heat capacity?

A.

Joulemeter reading at the start and end
B.

Time taken
C.

Starting temperature
D.

Mass in kg of the copper block

Correct Answer
B. Time taken

Explanation
To calculate the specific heat capacity of the copper block, the mass of the copper block, starting temperature, and the Joulemeter reading at the start and end are required. The time taken is not needed in this calculation, as the specific heat capacity is determined by the amount of heat energy transferred, which is obtained from the Joulemeter readings and not influenced by the time taken.

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6.

How much energy must be transferred to raise the temperature of 2 kg of water from 27^oC to 40^oC? Water has a heat capacity of 4,200 J/kg^oC

A.

109,200 kJ
B.

10,920 kJ
C.

1,092 kJ
D.

109.2 kJ

Correct Answer
D. 109.2 kJ

Explanation
The amount of energy required to raise the temperature of a substance can be calculated using the formula Q = m * c * ΔT, where Q is the energy transferred, m is the mass of the substance, c is the specific heat capacity of the substance, and ΔT is the change in temperature. In this case, the mass of water is 2 kg, the specific heat capacity of water is 4,200 J/kgoC, and the change in temperature is 40oC - 27oC = 13oC. Plugging these values into the formula, we get Q = 2 kg * 4,200 J/kgoC * 13oC = 109,200 J, which is equal to 109.2 kJ.

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7.

When a particular car engine is working normally, 1.5 kg of coolant at a temperature of 114^oC with a specific heat capacity of the of 3,800 J/kg^oC passes through the radiator each second. If 91.2 kJ of energy is transferred to the surroundings, what is the temperature of the coolant leaving the radiator?

A.

16^oC
B.

98^oC
C.

0.016^oC
D.

120^oC

Correct Answer
B. 98^oC

Explanation
The specific heat capacity of a substance is the amount of heat required to raise the temperature of 1 kilogram of the substance by 1 degree Celsius. In this case, the coolant has a specific heat capacity of 3,800 J/kgoC.

We are given that 91.2 kJ of energy is transferred to the surroundings. To find the temperature of the coolant leaving the radiator, we can use the equation:

Heat transferred = mass * specific heat capacity * change in temperature

Converting the heat transferred to joules:

91.2 kJ = 91,200 J

Rearranging the equation to solve for the change in temperature:

Change in temperature = Heat transferred / (mass * specific heat capacity)

Substituting the given values:

Change in temperature = 91,200 J / (1.5 kg * 3,800 J/kgoC)

Change in temperature = 40 oC

Since the initial temperature of the coolant is 114 oC, the temperature of the coolant leaving the radiator would be:

114 oC - 40 oC = 74 oC

Therefore, the correct answer is 98 oC.

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8.

A homeowner uses a wood burning stove to heat his house. The casing of the stove gets hot when the wood inside is burning and is made from 120 kg of cast iron. It took 3,276 kJ of energy to raise the temperature of the stove casing from 18^oC to 70^oC. What is the specific heat capacity of the cast iron in J/kg^oC?

A.

0.525
B.

525
C.

1.904
D.

1,904

Correct Answer
B. 525

Explanation
The specific heat capacity of a substance is the amount of heat energy required to raise the temperature of 1 kg of that substance by 1 degree Celsius. In this case, the stove casing, which is made from 120 kg of cast iron, required 3,276 kJ of energy to raise its temperature from 18oC to 70oC. To find the specific heat capacity, we divide the amount of energy by the mass and the change in temperature: 3,276 kJ / (120 kg * (70oC - 18oC)) = 525 J/kgoC. Therefore, the specific heat capacity of the cast iron is 525 J/kgoC.

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9.

Substances with a low specific heat capacity can store how much thermal energy?

A.

They can not store any thermal energy
B.

They can store some thermal energy
C.

They can store a lot of themal energy
D.

They can store an unlimited amount of thermal energy

Correct Answer
B. They can store some thermal energy

Explanation
Substances with a low specific heat capacity can store some thermal energy. Specific heat capacity refers to the amount of heat energy required to raise the temperature of a substance by a certain amount. When a substance has a low specific heat capacity, it means that it requires less heat energy to increase its temperature. Therefore, it can store some thermal energy, although not as much as substances with higher specific heat capacities.

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10.

The specific heat capacity of water is 4,200 J/kg^oC. The specific heat capacity of mineral oil is 2,100 J/kg^oC. Based on this information, which statement is correct?

A.

Mineral oil would be of little use for storing heat
B.

Water would be no use for storing heat
C.

Kilogram for kilogram, mineral oil can absorb more thermal energy than water
D.

Water can store more heat than the same mass of mineral oil

Correct Answer
D. Water can store more heat than the same mass of mineral oil

Explanation
Water has a higher specific heat capacity than mineral oil, which means that it can absorb and store more thermal energy per unit mass. Therefore, the statement "Water can store more heat than the same mass of mineral oil" is correct.

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Can You Answer These Questions On 8th Grade Physics?

What are the units of specific heat capacity?

As well as the specific heat capacity, what else affects the amount of thermal energy a material can store?

What symbol is used to represent the specific heat capacity of a material?

A block of copper was heated from 18oC to 33oC using 35 thousand joules of energy. The specific heat capacity of copper is 385 J/kgoC. What was the mass of the block of copper?

In a laboratory experiment, a group of students used a copper block with a hole drilled in for a thermometer and a second hole in for the heater. Which of the following is not required to calculate the specific heat capacity?

How much energy must be transferred to raise the temperature of 2 kg of water from 27oC to 40oC? Water has a heat capacity of 4,200 J/kgoC

Substances with a low specific heat capacity can store how much thermal energy?

The specific heat capacity of water is 4,200 J/kgoC. The specific heat capacity of mineral oil is 2,100 J/kgoC. Based on this information, which statement is correct?

A block of copper was heated from 18^oC to 33^oC using 35 thousand joules of energy. The specific heat capacity of copper is 385 J/kg^oC. What was the mass of the block of copper?

How much energy must be transferred to raise the temperature of 2 kg of water from 27^oC to 40^oC? Water has a heat capacity of 4,200 J/kg^oC

The specific heat capacity of water is 4,200 J/kg^oC. The specific heat capacity of mineral oil is 2,100 J/kg^oC. Based on this information, which statement is correct?