Kinetic Theory and First Law of Thermodynamics MCQs

Question 1

A cup of hot tea left in a room eventually:

Accepted Answer

reaches the room's temperature

Answer

becomes hotter

Answer

becomes colder than the room

Answer

stays hot forever

Question 2

A body at 80 °C is placed in contact with a body at 20 °C (isolated system). Their final common temperature is:

Accepted Answer

between 20 °C and 80 °C

Answer

80 °C

Answer

20 °C

Answer

100 °C

Question 3

A gas receives 600 J of heat and its internal energy rises by 600 J. The work done by the gas is:

Accepted Answer

0 J

Answer

-600 J

Answer

1200 J

Answer

600 J

Question 4

The SI unit of thermodynamic temperature is:

Accepted Answer

kelvin

Answer

calorie

Answer

joule

Answer

degree Celsius

Question 5

In the sign convention Delta U = Q + Won, a gas that is compressed has:

Accepted Answer

Won 0

Answer

Won = 0

Answer

Won < 0

Answer

Q = 0 always

Question 6

1 J of work equals:

Accepted Answer

1 Pa m^3

Answer

1 Pa m

Answer

1 Pa/m^3

Answer

1 N/m

Question 7

3 mol of an ideal gas at 350 K occupies 0.1 m^3. Its pressure is (R = 8.31 J mol^-1 K^-1):

Accepted Answer

87,300 Pa

Answer

8730 Pa

Answer

8.73 10^5 Pa

Answer

1.75 10^5 Pa

Question 8

Isothermal curves on a p–V diagram at higher temperatures lie:

Accepted Answer

further from the origin

Answer

on the axes

Answer

on the same curve

Answer

closer to the origin

Question 9

The internal energy of 1 mol of a monatomic ideal gas is U = 32nRT. When it is heated from 300 K to 400 K, its internal energy increases by:

Accepted Answer

1250 J

Answer

2490 J

Answer

831 J

Answer

623 J

Question 10

The area under an isothermal p–V curve between two volumes represents:

Accepted Answer

the work done by the gas

Answer

the temperature

Answer

the heat capacity

Answer

the pressure

Question 11

When an ideal gas expands isothermally, the heat absorbed:

Accepted Answer

is all converted into work done by the gas

Answer

is wasted

Answer

decreases internal energy

Answer

increases internal energy

Question 12

For an adiabatic change:

Accepted Answer

Q = 0, Delta U = -W

Answer

Q = W

Answer

Delta U = 0

Answer

W = 0

Question 13

Thermal equilibrium is reached faster when:

Accepted Answer

the bodies are good thermal conductors and in good contact

Answer

they are in a vacuum flask

Answer

they are insulated from each other

Answer

they have no contact

Question 14

In the compression stroke of an engine, the piston:

Accepted Answer

does work on the gas

Answer

receives work from the gas

Answer

cools the gas

Answer

does no work

Question 15

For an isothermal change of an ideal gas:

Accepted Answer

Delta U = 0, Q = W

Answer

Q = 0

Answer

W = 0

Answer

Delta U = Q

Question 16

The Boltzmann constant links:

Accepted Answer

the energy of a molecule with absolute temperature

Answer

mass with energy

Answer

charge with current

Answer

frequency with energy

Question 17

Why does a gas fill any container it is put in?

Accepted Answer

its molecules move randomly and freely in all directions

Answer

it is attracted by the walls

Answer

it has a fixed volume

Answer

it is heavier than air

Question 18

Which quantity decides the direction of heat flow?

Accepted Answer

temperature

Answer

heat capacity

Answer

mass

Answer

internal energy

Question 19

A bubble rising from the bottom of a lake (constant temperature) grows bigger because:

Accepted Answer

the water pressure on it decreases

Answer

the water pushes it outward

Answer

the temperature rises

Answer

gas is added

Question 20

The number of molecules in 2 mol of gas is:

Accepted Answer

1.20 10^24

Answer

2.76 10^-23

Answer

3.01 10^23

Answer

6.02 10^23

Question 21

If the internal energy of a fixed mass of ideal gas increases, its temperature must:

Accepted Answer

increase

Answer

become zero

Answer

stay the same

Answer

decrease

Question 22

The Boltzmann constant is related to the molar gas constant by:

Accepted Answer

k = RNA

Answer

k = NAR

Answer

k = R + NA

Question 23

2 mol of an ideal gas at 300 K occupies 0.05 m^3. Its pressure is (R = 8.31 J mol^-1 K^-1):

Accepted Answer

99,700 Pa

Answer

9970 Pa

Answer

1.99 10^5 Pa

Answer

9.97 10^5 Pa

Question 24

At high pressure a real gas departs from ideal behaviour because:

Accepted Answer

the molecules' own volume becomes significant

Answer

the molecules stop moving

Answer

the gas becomes a solid

Answer

temperature becomes zero

Question 25

Doubling the number of gas molecules in a fixed container at constant temperature:

Accepted Answer

doubles the pressure

Answer

quadruples the pressure

Answer

halves the pressure

Answer

does not change pressure

Kinetic Theory and First Law of Thermodynamics MCQs — Physics (page 7)

151. A cup of hot tea left in a room eventually:

152. A body at 80 °C is placed in contact with a body at 20 °C (isolated system). Their final common temperature is:

153. A gas receives 600 J of heat and its internal energy rises by 600 J. The work done by the gas is:

154. The SI unit of thermodynamic temperature is:

155. In the sign convention Delta U = Q + Won, a gas that is compressed has:

156. 1 J of work equals:

157. 3 mol of an ideal gas at 350 K occupies 0.1 m^3. Its pressure is (R = 8.31 J mol^-1 K^-1):

158. Isothermal curves on a p–V diagram at higher temperatures lie:

159. The internal energy of 1 mol of a monatomic ideal gas is U = 32nRT. When it is heated from 300 K to 400 K, its internal energy increases by:

160. The area under an isothermal p–V curve between two volumes represents:

161. When an ideal gas expands isothermally, the heat absorbed:

162. For an adiabatic change:

163. Thermal equilibrium is reached faster when:

164. In the compression stroke of an engine, the piston:

165. For an isothermal change of an ideal gas:

166. The Boltzmann constant links:

167. Why does a gas fill any container it is put in?

168. Which quantity decides the direction of heat flow?

169. A bubble rising from the bottom of a lake (constant temperature) grows bigger because:

170. The number of molecules in 2 mol of gas is:

171. If the internal energy of a fixed mass of ideal gas increases, its temperature must:

172. The Boltzmann constant is related to the molar gas constant by:

173. 2 mol of an ideal gas at 300 K occupies 0.05 m^3. Its pressure is (R = 8.31 J mol^-1 K^-1):

174. At high pressure a real gas departs from ideal behaviour because:

175. Doubling the number of gas molecules in a fixed container at constant temperature:

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