Physics Questions

$$\begin{gathered} 32oF \\ We know that \\ T(°F) = T(°C) × 1.8 + 32 \\ 32(°F) = 0(°C) \end{gathered}$$

The HF band is based on frequencies 3 to 30 Mhz. AM radio stations are in the HF band but normally are stated in kilohertz.

The rapid flow of air between the two moving ships causes a reducton of pressure (Bernoulli's principle) , so they (the ships) are drawn closer together

Black  surfaces are good emitters of heat ( They are also good absorbers of heat). If the black surface is rough too, the emitting will be better. So (b) is the correct answer. Shining surfaces reflect back radiation. So if the black surface is also shining the effectiveness of emitting heat is lessened.

Blood is a heterogeneous mixture because the blood cells are physically separate from the blood plasma. The cells have different properties than the plasma. The cells can be separated from the plasma by centrifuging, which is a physical change.

The P wave in the ECG represents atrial depolarization, which results in atrial contraction, or atrial systole.

The P wave is a summation wave generated by the depolarization front as it transits the atria.

A star is a self luminous astronomical object and shines due to internal radiation from the enrgy sources. All stars are held together by their own gravity called Gravitational force.