back to directory
NEET PHYSICSThermodynamicsEasy

Question

If ΔU\Delta U and ΔW\Delta W represent the increase in internal energy and work done by the system respectively in a thermodynamical process, which of the following is true?

A

ΔU=ΔW\Delta U = -\Delta W, in an adiabatic process

B

ΔU=ΔW\Delta U = \Delta W, in an isothermal process

C

ΔU=ΔW\Delta U = \Delta W, in an adiabatic process

D

ΔU=ΔW\Delta U = -\Delta W, in an isothermal process

Step-by-Step Solution

According to the first law of thermodynamics, the heat supplied to a system (ΔQ\Delta Q) is equal to the sum of the increase in internal energy (ΔU\Delta U) and the work done by the system (ΔW\Delta W). This is expressed as ΔQ=ΔU+ΔW\Delta Q = \Delta U + \Delta W. In an adiabatic process, there is no heat exchange between the system and its surroundings, which means ΔQ=0\Delta Q = 0. Substituting this into the first law equation, we get 0=ΔU+ΔW0 = \Delta U + \Delta W, which simplifies to ΔU=ΔW\Delta U = -\Delta W. For an isothermal process, the temperature remains constant, so the change in internal energy for an ideal gas is zero (ΔU=0\Delta U = 0), making ΔQ=ΔW\Delta Q = \Delta W. Thus, the only correct statement is option A.

Exam Context & Concepts Covered

This question aligns with the NEET PHYSICS syllabus, specifically targeting concepts from Thermodynamics. Mastering this topic is crucial for scoring well in the upcoming medical entrance examinations. Solving conceptually related problems will help you understand the nuances of these concepts and improve your problem-solving speed.

PHYSICSThermodynamicsrepresentincreaseinternalenergysystem

More Thermodynamics Questions

View all

The volume ($V$) of a monatomic gas varies with its temperature ($T$), as shown in the graph. The ratio of work done by the gas to the heat absorbed by it when it undergoes a change from state $A$ to state $B$ will be:

A.$\frac{2}{5}$
B.$\frac{2}{3}$
C.$\frac{1}{3}$
D.$\frac{2}{7}$
MediumSolve

A carnot engine having an efficiency of $\frac{1}{10}$ as a heat engine, is used as a refrigerator. If the work done on the system is $10\text{ J}$, the amount of energy absorbed from the reservoir at lower temperature is:

A.$1\text{ J}$
B.$90\text{ J}$
C.$99\text{ J}$
D.$100\text{ J}$
MediumSolve

An engine has an efficiency of $\frac{1}{6}$. When the temperature of the sink is reduced by $62^{\circ}\text{C}$, its efficiency is doubled. The temperature of the source is:

A.$124^{\circ}\text{C}$
B.$37^{\circ}\text{C}$
C.$62^{\circ}\text{C}$
D.$99^{\circ}\text{C}$
MediumSolve

A refrigerator works between $4^{\circ}\text{C}$ and $30^{\circ}\text{C}$. It is required to remove $600 \text{ calories}$ of heat every second to keep the temperature of the refrigerated space constant. The power required will be: (Take, $1 \text{ cal} = 4.2 \text{ Joules}$)

A.23.65 W
B.236.5 W
C.2365 W
D.2.365 W
MediumSolve

When $1 \text{ kg}$ of ice at $0^{\circ}\text{C}$ melts into water at $0^{\circ}\text{C}$, the resulting change in its entropy, taking the latent heat of ice to be $80 \text{ cal/g}$, is:

A.$8 \times 10^4 \text{ cal/K}$
B.$80 \text{ cal/K}$
C.$293 \text{ cal/K}$
D.$273 \text{ cal/K}$
EasySolve

One mole of an ideal diatomic gas undergoes a transition from $A$ to $B$ along a path $AB$ as shown in the figure. The change in internal energy of the gas during the transition is

A.$20\text{ kJ}$
B.$-20\text{ kJ}$
C.$20\text{ J}$
D.$-12\text{ kJ}$
MediumSolve

The coefficient of performance of a refrigerator is $5$. If the temperature inside freezer is $-20^\circ\text{C}$, the temperature of the surroundings to which it rejects heat is

A.$31^\circ\text{C}$
B.$41^\circ\text{C}$
C.$11^\circ\text{C}$
D.$21^\circ\text{C}$
MediumSolve

A mass of diatomic gas ($\gamma=1.4$) at a pressure of $2\text{ atm}$ is compressed adiabatically so that its temperature rises from $27^\circ\text{C}$ to $927^\circ\text{C}$. The pressure of the gas in the final state is:

A.$28\text{ atm}$
B.$68.7\text{ atm}$
C.$256\text{ atm}$
D.$8\text{ atm}$
MediumSolve

This neet physics practice question is part of the TopperSquare free question bank. TopperSquare offers 15,000+ chapter-wise NEET MCQs across Physics, Chemistry, and Biology with detailed step-by-step explanations, full mock tests, NEET PYQs (2010–2024), and an AI-powered performance analytics dashboard. browse all neet practice questions → · practice physics sets →