Explanation

• Television signals cannot be received ordinarily beyond a particular distance due to the curvature of the earth.

Key Points

• Signal waves travel in a straight line from the transmitting antenna to the receiving antenna. The signal transmitted from a TV tower cannot be received beyond a certain distance because the surface of the Earth is curved.
• This is due to, after going a certain distance the frequency of television signals decreases while their wavelength increases.
• Signal waves transmitted from a transmitter get absorbed or blocked by the curvature of Earth and are not received. 

Additional Information

• Signal:
  • Information converted in electrical form and suitable for transmission is called a signal.
  • Signals can be either analog or digital.

Explanation

The sun is visible a little before it rises and a little after it sets because of atmospheric refraction.

Refraction is the phenomenon that occurs when light changes direction as it passes from one transparent medium to another.

Explanation

Newton's Third Law of Motion states: "For every action, there is an equal and opposite reaction."

From this law, we can infer:

1. Statement 1: For every interaction, there is a pair of forces acting on the two interacting objects. (TRUE)
2. Statement 2: The magnitude of the force on the first object equals the magnitude of the force on the second object. (TRUE)
3. Statement 3: Forces always come in pairs - equal and opposite action-reaction force pairs. (TRUE)
4. Statement 4: Action and its reaction act on two same bodies. (FALSE - Action and reaction forces act on different bodies)
5. Statement 5: Action and its reaction act on two different bodies. (TRUE)

So, all statements except Statement 4 can be inferred from Newton's Third Law of Motion.

Explanation

Calcium phosphate, specifically hydroxyapatite, is the main component of bones and teeth.

It is a calcium salt of phosphoric acid.

It is the primary mineral constituent of bone tissue, making up about 70-80% of bone dry weight.

Calcium phosphate gives bones and teeth their strength and rigidity.

Explanation

A convex lens has either one or both of its surfaces curving outwards, that is, wider divergence from the plan at the center.

These lenses are used to correct long-sightedness (hypermetropia).

ND25-2-2023

Explanation

Philemon Yang appointed president of UN General Assembly in September 10, 2024.

Replaced Dennis Francis

Explanation

AIDS is a pandemic disease caused by the infection of (HIV), which damages the human immune system.

World AIDS Day is observed on 1 December since 1988.

Theme 2021: End Inequalities, End AIDS

Theme 2022: Equalize

Explanation

These are names of parliaments in different countries:

• Tsogdu (Mongolia),
• Folketing (Denmark),
• Hrvatski (Croatia),
• Yuan (China),
• Storting (Norway).

Explanation

The Constitution of India is the longest written constitution of any country in the world, with 146,385 words in its English-language version,

while the Constitution of Monaco is the shortest written constitution with 3,814 words.

Explanation