Air pressure is measured in which of the following units?

Correct Answer: 3 to 30 MHz

Explanation:

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.

Correct Answer: Natural Gas

Explanation:

Natural Gas is a Non Renewable Resource of Energy because that does not renew itself once used, unlike the other choices. 

It is a resource that will not be naturally replenished.

Correct Answer: astronomical units

Explanation:

The Length of the Day is determined in Astronomical Units.

The length of a day corresponds to the time the Earth takes to turn around on its axis, which is approximately 24 hours. But it's not exactly 24 hours. 

This phenomenon is due to tides raised by the Moon which slow Earth's rotation. Because of the way the second is defined, the mean length of a day is now about 86 400.002 seconds, and is increasing by about 1.7 milliseconds per century.

Correct Answer: They contain free electrons

Explanation:

Metal particles are held together by strong metallic bonds, which is why they have high melting and boiling points. The free electrons in metals can move through the metal, allowing metals to conduct electricity.

Because the electrons in the atom's higher energy levels can separate from the atoms easily, they can be pulled out with very little energy. Because the molecular structure of the metal is such that 'free electrons' are free to move, thus being categorized as electrically conductive.

 

For example, copper is used for electrical wiring because it is a good conductor of electricity.

Correct Answer: Glass

Explanation:

Because the refractive index of glass is highest, light travels slowly in Glass. 

We know that the speed of light depends on the refraction index. The higher the index of refraction is, the slower the speed of light is.

R.I of air and vacuum = 0 (air is a teeny bit more but can be taken as 0)
R.I of water = 1.33
R.I of glass = 1.4.

 

Hence, Light travels slowest in Glass.

Correct Answer: An ignition safety switch is a safety device can shut off the engine if the operator falls off the PWC or out of the powerboat, or is otherwise thrown from the proper operating position How it works: It allows the engine of the vehicle to shut off or to be turned off immediately as it is to prevent further complications to happen as this is being used when an emergency is launched Where it is used: Most powerboats and PWCs come equipped by the manufacturer with an emergency engine cut-off switch

Correct Answer: the capacity of layers of metal ions to slide over the other

Correct Answer: doing more work in less time.

Explanation:

Doing more work in less time, results in an increase in power to do a work.

Correct Answer: Intersection

Correct Answer: geothermal energy

Explanation:

Based on conventionality in deriving energy, energy sources could be classified as

 

Conventional ::

coal, oil, hydro, nuclear, etc... sources which can be used up or exhaustible.

(and)

Non - conventional ::

solar, wind, tidal, geothermal, biogas, etc... sources which are not exhausted.

 

Among the given options, Geothermal energy is the alternative energy source among all the choices that are given in the question, that is exhaustible.