First law questions

What is the adiabatic index of nitrogen?

• A) 1.2

• B) 1.4

• C) 1.6

• D) 1.8

• N/A

What is a common reason given for the compression of air to be adiabatic?

• A) The air is heated during compression.

• B) The air is cooled during compression.

• C) The compression occurs too quickly for heat exchange.

• D) The compression occurs too slowly for heat exchange.

• N/A

What is the volume of air in the buffer when the valve is on the point of opening?

• A) 2.5 x 10^-3 m^3
• B) 3.5 x 10^-3 m^3
• C) 4.5 x 10^-3 m^3
• D) 5.1 x 10^-3 m^3
• N/A

What is the adiabatic index of air?

• A) 1.2
• B) 1.4
• C) 1.6
• D) 1.8
• N/A

Why is the heater left at low power until the plastic is soft enough to form?

• A) To avoid blistering the plastic sheet.
• B) To reduce the time taken for the plastic to form.
• C) To save energy.
• D) To prevent the plastic from melting.
• N/A

Why does the air in the cavity cool during the vacuum-forming process?

• A) Due to the transfer of energy from the heater.
• B) Due to the rapid expansion of the air.
• C) Due to the transfer of energy to the plastic.
• D) Due to the increase in pressure in the cavity.
• N/A

What is the initial pressure of the air in the cavity?

• A) 100 Pa
• B) 100 kPa
• C) 313 Pa
• D) 313 kPa
• N/A

What is the adiabatic index of helium?

• A) 1.2
• B) 1.4
• C) 1.6
• D) 1.8
• N/A

Why can the compression of the gas in the gas strut be assumed to be adiabatic?

• A) The compression occurs too slowly for heat exchange.
• B) The gas is cooled during compression.
• C) The gas is heated during compression.
• D) The compression occurs too quickly for heat exchange.
• N/A