Internal Energy NEET Questions

Physics - Thermodynamics

Internal Energy MCQ Questions


13.
A bullet (mass m) fired at speed v stops in wood. The change in internal energy of the bullet-wood system is approximately:
A.
ΔU = mv
B.
ΔU = 2mv²
C.
Zero — kinetic energy is destroyed
D.
ΔU = (1/2)mv²
😑 View Answer Rough Work Error
ANSWER :
D. ΔU = (1/2)mv²
14.
For an ideal gas, when two different states have the same temperature but different pressures and volumes (e.g., reached by different paths), their internal energies are:
A.
Different because volumes are different
B.
Different because the paths to reach them were different
C.
Different because pressures are different
D.
Equal — for ideal gas, U depends only on T; same T means same U regardless of P or V
😑 View Answer Rough Work Error
ANSWER :
D. Equal — for ideal gas, U depends only on T; same T means same U regardless of P or V
15.
The First Law of Thermodynamics in terms of internal energy is:
A.
ΔU = ΔQ × ΔW
B.
ΔU = ΔW − ΔQ
C.
ΔU = ΔQ + ΔW
D.
ΔU = ΔQ − ΔW (change in U = heat supplied minus work done by system)
😑 View Answer Rough Work Error
ANSWER :
D. ΔU = ΔQ − ΔW (change in U = heat supplied minus work done by system)
16.
In the First Law ΔU = ΔQ − ΔW, both ΔQ and ΔW individually depend on the path. However, their combination (ΔQ − ΔW = ΔU) is:
A.
Zero always
B.
Path-independent — ΔU depends only on initial and final states (state variable property)
C.
Also path-dependent
D.
Maximum for isothermal paths
😑 View Answer Rough Work Error
ANSWER :
B. Path-independent — ΔU depends only on initial and final states (state variable property)
17.
A system goes from state (P₁,V₁,T₁) to (P₂,V₂,T₂) via three different processes: isothermal, isobaric, and adiabatic. The change in internal energy ΔU is:
A.
Largest for the isothermal process
B.
Zero for all processes
C.
Different for each process (depends on path)
D.
The same for all three processes (depends only on initial state and final state)
😑 View Answer Rough Work Error
ANSWER :
D. The same for all three processes (depends only on initial state and final state)
18.
In an isothermal process for an ideal gas, ΔT = 0. The change in internal energy ΔU is:
A.
Zero — for ideal gas, U depends only on T; constant T means no change in U
B.
Equal to the work done
C.
Negative — gas does work
D.
Positive — gas absorbs heat
😑 View Answer Rough Work Error
ANSWER :
A. Zero — for ideal gas, U depends only on T; constant T means no change in U