Question # 1

When heat is added into the system then change in entropy is

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negative

positive

zero

any one of them

If the formula PV = nRT, n denotes:

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Number of molecules per unit volume

Number of moles

Number of molecules

None of these

The process which is carried out at constant temperature is known as

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adiabatic process

isothermal process

isochoric process

none of them

A reversible cycle is the one in which

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some of the changes are reversible

all of the changes are reversible

all of the changes are irreversible

none of them

If the volume of the gas is to be increased by 4 times, then

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Temperature and pressure must be doubled

At constant P the temperature must be increased by 4 times

At constant T the pressure must be increased by four times

It cannot be increased

Melting point of ice

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Increases with increasing pressure

Decreases with increasing pressure

Is independent of pressure

Is proportional to pressure

At O° K which of the following properties of a gas will be zero?

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Kinetic energy

Potential energy

Vibrational energy

Density

At what temperature the adiabatic change is equivalent to the isothermal change?

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Zero degree Celsius

Zero Kelvin

Critical temperature

Above critical temperature

A diatomic gas molecule has

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translational energy

rotaional energy

vibrational energy

all of them

A carnot cycle consists of

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One step

two step

three steps

four steps

When two objects come to common temperature, the body is said to be in:

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Static equilibrium

Dynamic equilibrium

Thermal equilibrium

None of these

The disorder in the system increases due to the

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removal of heat

addition of heat

removal or addition of heat

none of them

R.M.S velocity of a particle is V at pressure P. If pressure increases by two times, then R.M.S velocity becomes

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2V

3V

0.5V

V

The efficiency of carnot engine cannot be 100% or one unless cold reservoir is at

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100 K

273 K

0 K

-273 K

Hydrogen and helium of same volume V at same temperature T and same pressure P are mixed to have same volume V. The resulting pressure of the mixtures will be

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R/2

P

2P

Depending on the relative mass of the gases

In an ideal gas, the molecules have:

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Kinetic energy only

Potential energy only

Both KE and PE

None of these

What temperature is the same on Celsius scale as well as on Fahrenheit scale?

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32°C

-32°C

-40°C

-212°C

One mole of any substance contain

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same number of molecules

different number of molecules

may be same or different

none of them

Pressure exerted by a gas is

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Independent of density of the gas

Inversely proportional to the density of the gas

Directly proportional to the square of the density of the gas

Directly proportional to the density of the gas

We can express the work in term of

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directly measurable variables

indirectly measurable variables

either of them

both of them

At constant volume temperature is increased. Then

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Collision on walls will be less

Number of collisions per unit time will increase

Collision will be in straight lines

Collision will not change

The percentage of available heat energy converted into work by a diesel engine is roughly

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35 %`

40 %

35 - 40 %

25 %

Rice takes longest to cook

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In a submarine 100 m below the surface of the sea

At sea level

At Murree

At Mount Everest

Tick the correct pair when M denotes the molecular mass and other symbols carry usual meanings:

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N = nN_Am = MN_A

n = N N_A, M = mN_A

M = N_A/N , N_A= m/n

N = nN_A, M = mN_A

Which quantity is important in stating the entropy of the system

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initial entropy

final entropy

change in entropy

none of them

According to the second law, which is must to produce work

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a source contains a large amount of heat energy

two sources at the same temperature

two sources at the different temperatures

a source contains a small amount of energy

If N is the total number of molecules and V is the volume of the container, then the expression for the pressure of gas is

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P=P/V<1/2mv²>

P=2N/V<1/2mv²>

P=2/3N/V<1/2mv²>

P=2/3N/V<mv²>

Which of the following does not have the same units:

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Work

Heat

Kinetic energy

Power

While deriving the equation for pressure of a gas we consider the

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rotational motion of molecules

vibrational motion of molecules

linear motion of molecules

all of them

A real gas can be approximated to an ideal gas at

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Low density

High pressure

High density

Low temperature

When heat is removed from the system

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negative

positive

zero

any one of them

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