Explanation

Geothermal energy is the heat produced deep in Earth's core.

it is a clean, renewable resource that can be harnessed for use as heat and electricity

Explanation

• Navigation satellites are used for identifying the location of objects on Earth.
• Example: GPS (Global Positioning System) for navigation.

Explanation

• Comets are the small broken pieces of ice, dust, and gases found beyond the orbits of Neptune and Pluto in the solar system.
• Comets originate from regions such as the Kuiper Belt and the Oort Cloud, where they are composed of volatile substances like ice and dust.

Explanation

• A mirror with a reflecting surface that bulges outwards, like the back side of a spoon, is called a Convex Mirror.
• This type of mirror is used in applications such as security mirrors, rear-view mirrors, and surveillance mirrors, as it provides a wider field of view.

Explanation

• Comets are often referred to as "dirty snowballs" due to their composition.
• Comets are characterized by their highly elliptical orbits and bright tails of gas and dust that form when they approach the Sun.

Explanation

• Our sun is one of the billions of stars in the Milky Way galaxy.
• The Milky Way is estimated to contain between 200-400 billion stars.

Explanation

• Iron is a ferromagnetic material, which means it is strongly attracted to magnets.
• Therefore, an iron kettle will be attracted to a magnet.

Explanation

• Radioactivity was discovered by Henri Becquerel, a French physicist, in 1896.
• He discovered this when he was studying uranium and noticed that it emitted radiation without an external source of energy.
  
• The term radioactivity was coined by Marie Curie, who, along with her husband, investigated this phenomenon.
• Rutherford, a British physicist, studied the properties of radioactive decay and named the particles alpha, beta and gamma.

Explanation

The average translational kinetic energy of molecules is directly proportional to the temperature (in Kelvin).

Since the temperature is increased from 300 K to 750 K, the average translational kinetic energy will also increase by a factor of 750/300 = 2.5.

So, the average translational energy at 750 K will be:

6 x 10^-20 J x 2.5 = 1.5 x 10^-19 J

Explanation

When a dielectric sheet is placed between two charges, the electrostatic force between them will "decrease" because the presence of the dielectric reduces the electric field strength between the charges, thus decreasing the force experienced by them.