The diagram shows a ship moving towards a cliff. The sound from the siren of the reflected by the cliff and heard 6.0s later by the sailor on the ship. How far from the cliff is the ship, taking the speed of sound in air to be 330m/s?

• A: "equal to zero Kelvin on the absolute temperature scale." This is the definition of absolute zero, so it is true.
• B: "equivalent to $273^\circ \text{C}$ on the absolute temperature scale." Absolute zero is $0 \text{ K}$, which is equivalent to $-273.15^\circ \text{C}$. Therefore, $273^\circ \text{C}$ is not absolute zero; this statement is not true.
• C: "represented by $^\circ \text{C}$." Absolute zero is represented as $0 \text{ K}$ on the absolute temperature scale. While it can be expressed in Celsius, its representation on the absolute scale is Kelvin. So, this statement is also not true.
• D: "the lowest possible temperature at which the volume of a gas is assumed to be zero." This is a consequence of the ideal gas law and is considered true in the context of ideal gases.

Both B and C are not true. However, statement B presents a direct numerical inaccuracy ($273^\circ \text{C}$ instead of $-273^\circ \text{C}$), which is a fundamental error in the value of absolute zero in Celsius. Statement C is about the unit of representation, which is Kelvin for the absolute scale. In physics, the conversion error in B is typically considered the more significant "not true" statement in such questions.

The correct option is B.

A8: Wave Travel Time

Given frequency $f = 500 \text{ Hz}$ and wavelength $\lambda = 0.05 \text{ m}$.
The wave speed $v$ is given by the formula:

Given distance $d = 1250 \text{ m}$.
The time $t$ is given by the formula:

The correct option is C.

A9: Frequency of Red Light

Wavelength of red light $\lambda = 7.5 \times 10^{-7} \text{ m}$.
The speed of light (an electromagnetic wave) in a vacuum or air is approximately $c = 3.0 \times 10^8 \text{ m/s}$.

The relationship between speed of light ($c$), frequency ($f$), and wavelength ($\lambda$) is:

Rearranging for frequency:

The correct option is B.

A10: Distance from Cliff (Echo)

The sound travels from the ship to the cliff and then reflects back to the ship. The total time taken for this round trip is $6.0 \text{ s}$.
Given the speed of sound $v = 330 \text{ m/s}$.
Total distance $d_{\text{total}}$ is:

The distance from the ship to the cliff is half of the total distance traveled by the sound, as the sound makes a round trip.

The correct option is C.