Explanation

• The Earth's axis is an imaginary line that runs through the North Pole and the South Pole, around which the Earth rotates.
• It is an imaginary reference point, not a physical object or shape.

Explanation

• The orbit of the Earth around the Sun is an ellipse, meaning that it is an elongated circle, with the Sun located at one of the two foci (plural of focus) of the ellipse.
• This means that the distance between the Earth and the Sun varies throughout the year.
• With the closest point (perihelion) occurring around early January.
• With the farthest point (aphelion) occurring around early July.
  

Explanation

Einstein’s photoelectric equation is "hv = hvo + (1/2 mv^2) max", where:

• hv is the energy of the incident photon
• h is Planck's constant
• vo is the threshold frequency
• m is the mass of the emitted photoelectron
• max is the maximum kinetic energy of the emitted photoelectron.

Explanation

Simple harmonic motion (SHM) is also known as oscillatory motion or periodic motion.

It can also be referred to as harmonic oscillation.

It is a system exhibiting SHM that is often called a simple harmonic oscillator. 

Explanation

In semiconductors, when an electron leaves its position in the valence band, it creates a "hole" which can act as a positive charge carrier.

This is why holes are primarily associated with semiconductors. 

Explanation

Explanation

For a rigid body that rotates about a fixed axis, the angle swept out by a line passing through any point on the body and intersecting the axis of rotation perpendicularly is called angular displacement.

Explanation

Reliability is a measurement of consistency.

Reliability refers to the consistency of a measure

Validity refers to the accuracy of a measure

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Explanation

If the frequency of electricity is doubled, the efficiency of the load decreases.

This is because electrical devices and systems are designed to operate optimally at a specific frequency, and doubling it can disrupt their performance.

Explanation

The renewable energy sources are:

• Water energy
• Wind energy
• Tidal energy
• Hydroelectric
• Ocean energy
• Geothermal energy
• Biomass
• Biogas

The non-renewable energy sources are:

• Fossil fuels or Hydrocarbon fuel (Oil, Natural gas, Coal)
• Nuclear energy