Explanation

Studies show that it takes an average of 8 minutes and 20 seconds for sunlight to move from the sun to the earth.

Sunlight moves at the speed of light.

You can see that the distance of the sun from the earth = 149.6 x 106 km.

Photons emitted from the surface of the sun need to traverse the vacuum of the universe to reach our eyes.

Explanation

Frequency is defined as the number of wavelengths that pass a given point each second

Common symbols f, ν

SI unit hertz (Hz)

Other units

• cycle per second (cps)
• revolution per minute (rpm or r/min)

In SI base units s−1

Derivations from other quantities f = 1 / T

Dimension= T^-1

Explanation

The Moho Discontinuity is the boundary between the Earth's crust and mantle, named after seismologist Andrija Mohorovicic.

It is identified by a sudden increase in seismic wave velocities, indicating a change in rock composition.

Explanation

AND, OR, and NOT are logical operators (also known as Boolean operators). 

These operators are fundamental to computer programming, mathematics, and digital electronics because they work with and return Boolean values (either True or False, often represented as 1 and 0). 

Explanation

The Waxing moon refers to the phase when the visible portion of the moon is increasing.

It moving from new moon towards full moon.

Explanation

The Equator is an imaginary line that divides the Earth into the Northern and Southern Hemispheres.

It lies equidistant from the North and South Poles.

Explanation

Accretion is the process where a black hole pulls in surrounding gas, dust, and matter due to its strong gravitational pull.

This material forms an accretion disk around the black hole before being absorbed.

Explanation

• The Pakistan Space and Upper Atmosphere Research Commission (SUPARCO) was established in 1961.
• It was originally formed as a Committee in 1961 and gained Commission status in 1981.
• The SUPARCO is Pakistan's national space agency and is responsible for the development of space technology and its peaceful applications in the country.
• It is headquartered in Islamabad and has technical facilities in Karachi, Lahore, Multan, Quetta, Peshawar and Gilgit.

Explanation

Abrasion occurs when wind carries sand and dust, wearing down rock surfaces.

It is a common feature in desert and arid regions shaped by air action.

Explanation

Solar photovoltaic (PV) panels directly convert sunlight into electricity without turbines.

Other sources like hydropower, wind, and thermal rely on turbines to generate electricity.