Thermodynamics Test

Result

Thermodynamics Test - 65

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

The molar heat capacity of oxygen gas at $$STP$$ is nearly $$2.5\ R$$. As the temperature is increased, it gradually increases and approaches $$3.5\ R$$. The most appropriate reason for this behaviour is that at high temperature :

A
oxygen does not behave as an ideal gas

B
oxygen molecules dissociate in atoms

C
the molecules collide more frequently

D
molecular vibrations gradually become effective

Solution

Molar specific heat depends on degree of freedom (f)
If
T increases gas molecule starts vibrating due to which f increases and molar heat capacity
So option d is correct
Question 2
1 / -0

In a given process for ideal gas, $$dW=0$$ and $$dH > 0$$. Then for the gas :

A
The volume remain constant

B
The volume will increase

C
temperature will increase

D
Both $$(a)$$ and $$(c)$$ are correct

Solution
Question 3
1 / -0

During an isothermal expansion of an ideal gas :

A
its internal energy decreases

B
its internal energy does not change

C
the work done by the gas is equal to the quantity of heat absorbed by it

D
both $$(b)$$ and $$(c)$$ are correct

Solution
Question 4
1 / -0

An ideal gas undergoes an isothermal change in volume with pressure then:

A
$$P^{\gamma}V=$$ constant

B
$$PV^{\gamma}=$$ constant

C
$$(PV)^{\gamma}=$$ constant

D
$$PV=$$ constant

Solution
Question 5
1 / -0

The table given below shows two different processes. Calculate the unknown values with help of first law of thermodynamics. All the data are in joule :
Process $$\Delta Q$$ $$\Delta W$$ $$U_1$$ $$U_f$$ $$\Delta U=U_f-U_f$$
$$1.$$ $$35$$ ... $$-60$$ ... $$50$$
$$2.$$ $$-15$$ ... $$80$$ $$60$$ ...

A
for process $$1 \rightarrow \Delta W=-15\ J; U_f=-10\ J$$
for process $$2 \rightarrow \Delta W=5\ J; \Delta U=-20\ J$$

B
for process $$1 \rightarrow \Delta W=15\ J; U_f=-20\ J$$
for process $$2 \rightarrow \Delta W=-5\ J; \Delta U=-20\ J$$

C
for process $$1 \rightarrow \Delta W=-5\ J; U_f=20\ J$$
for process $$2 \rightarrow \Delta W=15\ J; \Delta U=-10\ J$$

D
$$data\ incomplete$$

Solution
Question 6
1 / -0

In the case of saturated vapour :

A
pressure depends upon volume at constant temperature

B
pressure varies non-linearly with temperature at constant volume

C
pressure becomes less then one atmosphere at boiling point

D
pressure varies linearly with temperature at constant volume

Solution
Question 7
1 / -0

The first law of thermodynamic is essentially a statement:

A
implying that heat cannot flow from a cold body to a hot body

B
of conservation of energy

C
that gives the mechanical equivalent of heat

D
regarding isothermal process

Solution
Question 8
1 / -0

When a gas is allowed to expand suddenly into a vacuum chamber, then

A
heat supplied is zero

B
temperature remain constant

C
volume does not change

D
both (a) and (b) are correct

Solution

As the container is insulated , Q = 0
As it is expanding freely, the work done is zero.
∆V = Q-W
∆V = 0
∆ = $Cv∆T$
$∆T=0$
Hence, there will be no increase or decrease in temperature or internal energy. It remains constant
Option B is the right answer
Question 9
1 / -0

If in an adiabatic process, the pressure is increased by $$2/3\%$$, then volume decreased by $$\left (Assume\ \ \dfrac {C_P}{C_V}=\dfrac {3}{2}\right)$$ :

A
$$\dfrac {4}{9}\%$$

B
$$\dfrac {2}{3}\%$$

C
$$4\%$$

D
$$\dfrac {9}{4}\%$$

Solution
Question 10
1 / -0

The first law of thermodynamics is a statement of

A
conservation of heat

B
conservation of work

C
conservation of momentum

D
conservation of energy.

Solution

The first law of thermodynamics applies the conservation of energy principle to systems where heat transfer and doing work are the methods of transferring energy into and out of the system. The first law of thermodynamics states that the change in internal energy of a system $$\Delta U$$, equals the net heat transfer into the system $$Q,$$ plus the net work done on the system $$W$$. In equation form, the first law of thermodynamics is,
$$\Delta U=Q+W$$
Here $$\Delta U$$ is the change in internal energy $$U$$ of the system. $$Q$$is the net heat transferred into the system—that is, $$Q$$ is the sum of all heat transfer into and out of the system. $$W$$ is the net work done on the system.