Physics
Thermodynamics and Gas Laws
616 Questions
Thermodynamics and gas laws questions test the understanding of ideal gas behavior, work done during thermodynamic processes, and specific heat ratios. Key areas include isothermal, adiabatic, and isobaric expansions along with real gas deviations. These mathematical physics concepts are standard in engineering and general science competitive exams.
Ideal gas equationIsothermal and adiabatic processesThermodynamic workGas kinetic theoryReal gas behavior
Thermodynamics and Gas Laws Questions
-
Charles' law
-
Newton's law
-
Gauss' law
-
Boyle's law
D
Correct answer
Explanation
Boyle's Law states that for a fixed amount of gas at constant temperature, pressure and volume are inversely proportional (PV = constant). As pressure increases, volume decreases proportionally, and vice versa. This fundamental gas law was formulated by Robert Boyle in 1662.
-
Newtonian force
-
Gravitational Force
-
Vander waal force
-
Kinetic force
C
Correct answer
Explanation
Van der Waals forces (intermolecular attractions and repulsions) cause real gases to deviate from ideal gas behavior, especially at high pressure and low temperature. Ideal gas assumptions neglect molecular size and intermolecular forces.
-
The product of the pressure and the volume of an ideal gas at constant temperature is a constant
-
The product of the pressure and the temperature of an ideal gas at constant volume is a constant
-
The product of the pressure and the volume of a real gas at constant temperature is a constant
-
The product of the pressure and the temperature of a real gas at constant temperature varies exponentially.
A
Correct answer
Explanation
Boyle's Law (1662) states that for a fixed amount of ideal gas at constant temperature, pressure and volume are inversely proportional: P₁V₁ = P₂V₂, or PV = constant. Option B confuses volume with temperature, while C incorrectly specifies real gases.
-
P1 V1 = P2 V2
-
P V = n R T
-
V1 / T1 = V2 / T2
-
V1 / V2 = T1 / T2
B
Correct answer
Explanation
The ideal gas law relates pressure (P), volume (V), amount of gas in moles (n), the universal gas constant (R), and temperature (T). PV = nRT is the correct and complete form.
-
P1 V1 = P2V2
-
P1 V1 = P2V1
-
P1 V2= P2V1
-
P1 /V1 = P2/V2
A
Correct answer
Explanation
Boyle's law states that for an ideal gas at constant temperature, the pressure and volume are inversely proportional: P₁V₁ = P₂V₂. This means when pressure increases, volume decreases proportionally, and vice versa, as long as temperature remains unchanged. Option A correctly represents this relationship.
-
V1T2= V2T1
-
V1T1= V2T2
-
V2T2= V1T1
-
None
A
Correct answer
Explanation
Charles's law states that for an ideal gas at constant pressure, volume is directly proportional to absolute temperature: V ∝ T, or V₁/T₁ = V₂/T₂. Cross-multiplying gives V₁T₂ = V₂T₁, which is option A. This means that as temperature increases, volume increases proportionally, and vice versa, when pressure is held constant.
-
gas-liquid
-
liquid-liquid
-
liquid-solid
-
solid-gas
-
John Dalton's law, Faraday's law
-
Charles's law, Boyle's law
-
Raoult's law, Charles's law
-
Boyle's law, Gay-Lussac's law
B
Correct answer
Explanation
An ideal gas perfectly follows Charles's law (V ∝ T at constant pressure) and Boyle's law (PV = constant at constant temperature). These two laws, along with Gay-Lussac's law, are fundamental gas laws that describe the behavior of ideal gases. Option B correctly identifies Charles's law and Boyle's law as essential for ideal gas behavior.
-
P1*V1/T1 = P2*V2/T2
-
PV = nRT
-
P1*V1 = P2*V2
-
P1*V1/T2 = P2*V2/T1
B
Correct answer
Explanation
The ideal gas law is PV = nRT, where P is pressure, V is volume, n is moles of gas, R is the gas constant, and T is temperature. This equation combines Boyle's law, Charles's law, and Avogadro's law into one unified relationship. Option B shows the correct ideal gas law equation.
B
Correct answer
Explanation
Dispersion forces (London forces) are weak attractive forces between molecules caused by temporary dipoles, not repulsive forces. Additionally, ideal gases by definition have no intermolecular forces at all. The statement is wrong on both counts.
B
Correct answer
Explanation
Hund's rule deals with electron configuration in atoms - it states that electrons will occupy degenerate orbitals singly before pairing up. It has nothing to do with gas pressures, which are covered by Dalton's law of partial pressures.
A
Correct answer
Explanation
At the microscopic level, gas molecules collide randomly with container walls causing local pressure variations, and temperature directly relates to the average kinetic energy (velocity) of molecules. Both statements are physically accurate.
-
38.65 x 10<sup style="font-family:">3 K
-
8.69 x 10<sup style="font-family:">4 K
-
1.93 x 10<sup style="font-family:">4 K
-
2.89 x 10<sup style="font-family:">4 K
-
11.59 x 10<sup style="font-family:">4 K
A
Correct answer
Explanation
K.E. of the electron is
5 eV = 5 x 1.6 x 10-19 J
But K.E. = (3/2)KT
∴ 5 x 1.6 x 10-19 = (3/2)(1.38 x 10-23) x T
T = 2 x 5 x 1.6 x 10-19/3 x 1.38 x 10-23 = 38.65 x 103 K