Explanation

A hydrogen atom is approximately 1,837 times heavier than an electron, according to multiple sources.

This difference is primarily due to the mass of the proton within the hydrogen atom,

Which is about 1,836 times more massive than an electron.

Explanation

Synaptic transmission involves:  

- Na⁺ (Sodium): For depolarization  

- K⁺ (Potassium): For repolarization  

- Ca²⁺ (Calcium): Triggers neurotransmitter release at synapse

Explanation

The boiling points for the given alkali metals are as follows: 

• Lithium (Li): 1,342°C
• Sodium (Na): 883°C
• Potassium (K): 774°C
• Rubidium (Rb): 688°C 

Among the choices, rubidium has the lowest boiling point. 

Explanation

UV rays and gamma rays are used to destroy bacteria and insects.

Alpha and beta rays are generally not used for these purposes. 

UV rays

Bacteria:

• UV-C light, a specific range of ultraviolet light, damages the DNA and RNA of microorganisms, including bacteria, preventing them from reproducing.
• This makes it an effective disinfectant for surfaces, air, and liquids.

Insects:

• High-intensity UV-C light can kill insects, though typical bug zappers use UV-A light, which mostly just attracts insects to an electric grid.
• Studies have also found that specific short wavelengths of blue and UV light are lethal to some insect pests. 

Gamma rays

Bacteria:

Gamma irradiation, most commonly using cobalt-60,

It is widely used to sterilize medical equipment and pasteurize food by damaging the DNA of bacteria and other microorganisms.

Insects:

Gamma irradiation is a proven method for eliminating pests like insects and mites in stored food products and for controlling insect populations in agriculture. 

Explanation

The typical pore size of a porcelain filter, also known as a ceramic filter, ranges from 0.2 to 10 micrometers (µm) in the micron scale.

The micron-sized pores of a porcelain filter make it effective for removing:

• Bacteria
• Protozoa
• Sediment and suspended solids
• Turbidity (cloudiness) 

Variations in pore size

The exact pore size can vary depending on the filter's specific design and application.

For example: 

Standard ceramic filters for drinking water often have a pore size of 0.2–0.5 microns.

Industrial porous ceramic filters can have a much wider range, from less than 1 µm up to 100 µm, depending on what they are filtering. 

Explanation

The electrical resistivity of copper is approximately 1.68 x 10⁻⁸ Ω·m at 20°C (68°F).

This low value signifies that copper is an excellent electrical conductor, with a long mean free path for electrons and high electrical conductivity. 

Here's a breakdown of the values: 

Standard Copper: 1.68 x 10⁻⁸ Ω·m

Annealed Copper: 1.72 x 10⁻⁸ Ω·m

Explanation

 The bursting of a tire is an example of an adiabatic process. 

An adiabatic process is a thermodynamic process where no heat transfer occurs between the system and its surroundings.

When a tire bursts suddenly, the expansion happens so quickly that there's essentially no time for heat to transfer in or out of the system.

This rapid expansion causes a drop in temperature inside the tire. 

Explanation

In an SN1 reaction, a racemic mixture is formed because of the carbocation intermediate, which has an empty p-orbital.

When the leaving group departs, the carbon center becomes a trigonal planar carbocation with an empty, unhybridized p-orbital perpendicular to the plane.

A nucleophile can attack this empty orbital from either the top face or the bottom face with nearly equal probability. 

Explanation

Ar has the least ionization energy.

Ionization energy generally decreases down a group and increases across a period on the periodic table. 

Ar (argon): is in Group 18 (noble gases) and is at the bottom of the group, meaning it has the lowest ionization energy among the options. 

Mg (magnesium): is in Group 2, above Ar. In contrast, it's in the same period as Si and Se; its smaller size compared to the other options results in a higher ionization energy. 

Si (silicon): and Se (selenium): are both in the same period (3), but Se has a higher ionization energy than Si due to its larger atomic number and greater effective nuclear charge. 

Explanation

In the human body, Ferritin is used to store Iron. 

Storage and function:

Ferritin is a protein that stores iron inside your cells and releases it in a controlled manner when your body needs it.

Protection:

By storing iron in a non-toxic form, ferritin helps protect the body from potential damage caused by free iron.

Distribution:

Ferritin is found in most tissues, with the highest concentrations in the liver, spleen, and bone marrow.

Clinical marker:

Levels of ferritin in the blood can be measured to estimate the total amount of iron stored in the body.