Modem is used mostly for ?

Correct Answer: TRUE

Explanation:

Microwaves are high-frequency signals in the 300 MHz to 300 GHz range. This is in contrast to radio signals, which are typically broadcast in all directions. Radio signals operate in the 3 Hz to 300 MHz range.

Microwave signals are used for both satellite and ground-based communications.

Correct Answer: FALSE

Explanation:

The given statement, The heat from the sun reaches earth through Convection is FALSE.

 

Heat from the sun actually reaches the earth through Radiation. The process occurs through electromagnetic radiation, specifically, in which molecules are warmed when the heat reaches them, and these molecules then warm other molecules touching them, which continues until we feel the sun's heat.

Correct Answer: Converging

Explanation:

A magnifying glass is a convex lens that is used to produce a magnified image of an object. It is also called a hand lens in laboratory contexts.

Correct Answer: plant bending toward the light

Explanation:

Phototropism is the ability of a photosynthesizing organism, to grow directionally in response to a light source. It is very common in plants, but can also occur in other organisms such as fungi.

Example :: Sunflower

Correct Answer: Neutron

Explanation:

In nuclear physics, nuclear fission is either a nuclear reaction or a radioactive decay process in which the nucleus of an atom splits into smaller parts (lighter nuclei). The fission process often produces free neutrons and releases a very large amount of energy.

 

Thus, The Nuclear Fission is caused by the impact of Neutrons.

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: 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: 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: 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: 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.