1. Determine the state of iron at a temperature of 1200°C. 1) solid; 2) liquid; 3) both solid and liquid; 4) impossible

1. Determine the state of iron at a temperature of 1200°C.
1) solid; 2) liquid; 3) both solid and liquid; 4) impossible to determine.

2. Determine which of the following statements is true:
1) liquid evaporates only at high temperatures;
2) boiling temperature is always positive;
3) the temperature of a liquid decreases during boiling;
4) the temperature of a liquid remains constant during boiling.

3. Which of the metals listed below has the lowest melting point:
1) gold; 2) copper; 3) platinum; 4) tungsten.

4. The graph shows the temperature vs. time relationship during the heating and cooling of ether. At the initial moment, ether was in a liquid state. Which part of the graph corresponds to the process of ether boiling?
1) 1 – 2; 2) 1 — 2 – 3; 3) 2 – 3; 4) 3 – 4.

5. A wet-bulb thermometer of a psychrometer shows a temperature of 16°C, while the dry-bulb thermometer shows 20°C. Using a psychrometric table, determine the relative humidity of the air.
1) 100%; 2) 62%; 3) 66%; 4) 74%.

6. What work will a heat engine with an efficiency of 25% perform if it consumes 80 MJ of heat?
1) 10 MJ; 2) 40 MJ; 3) 20 MJ; 4) 55 MJ.

7. How much energy is required to melt 200 g of lead at its melting temperature? (Specific heat of lead melting is 25 kJ/kg).
1) 5000 J; 2) 5.5 kJ; 3) 50000 J; 4) 0.55 kJ.

Part 2:

1. Establish a correspondence between physical quantities and the formulas by which these quantities are determined. Match each item in the first column with the corresponding item in the second column and write the selected numbers in the table under the respective letters.
PHYSICAL QUANTITY FORMULA
A) Amount of heat required 1) L · m
for boiling a liquid; 2) q · m
B) Specific heat of combustion of fuel; 3) Q / m · Δt
C) Amount of heat released 4) c · m · Δt
during cooling of a substance. 5) Q / m

Part B:

2. 690 kJ of energy was used during the boiling of water. Find the mass of the evaporated water. (The specific heat of vaporization of water is 2.3 × 10^6 J/kg).
1) 3 kg; 2) 0.3 kg; 3) 30 kg; 4) 300 kg.

Part C:

1. What mass of kerosene needs to be burned to produce the same amount of energy as is released when 500 g of coal is burned? (Specific heat of combustion of coal is 30 × 10^6 J/kg; kerosene is 46 × 10^6 J/kg).
1) 33 kg; 2) 0.33 kg; 3) 30 kg; 4) 300 kg.