Explanation

Beta particles are high-energy electrons or positrons that interact frequently with air molecules.

These collisions cause them to change direction randomly, resulting in a zigzag or erratic path. 

Explanation

If two streams of protons move parallel to each other in the same direction, they repel each other. 

Protons are positively charged particles, and according to Coulomb's law, particles with the same charge repel each other.

This repulsive electrostatic force dominates between the protons, causing them to push away from each other. 

Explanation

Alveoli:

Bronchioles terminate in tiny air sacs called alveoli.

These are the primary sites for gas exchange in the lungs. 

Alveolar sac:

Alveoli are clustered together to form alveolar sacs

These sacs are the functional units of the lung where oxygen and carbon dioxide exchange occurs. 

Explanation

A phrase is a group of words that does not give a complete sense and lacks a verb.

It is a unit of language that functions as a single unit, but does not express a complete thought.

Explanation

- The elementary charge on a single electron is -1.6 × 10⁻¹⁹ coulombs.

- It’s a fundamental physical constant.

Explanation

 Prokaryotic cells lack membrane-bound organelles like chloroplasts.

Chloroplasts are organelles found in eukaryotic cells, specifically plant cells, and are responsible for photosynthesis.

Prokaryotic cells, while simpler in structure, do possess other components such as"

• Ribosomes (for protein synthesis)
• A cell wall (for structural support)
• DNA (although not contained within a nucleus) 

Explanation

The velocity of an electron is maximum in 1st shell

because according to Bohr's model

So we have velocity of electron = 2.188 ×10^6 m/s.

By calculation, we gained velocity= 1.094×10^6 m/s.

So it is determined that the velocity is decreased as we move from lower to higher shell

Explanation

Melting ice below 0°C by applying pressure is a spontaneous physical change. 

Physical change:

This is correct because the process only changes the state of water from solid to liquid, without altering its chemical composition. 

Spontaneous:

• Under the applied pressure, the ice will naturally melt even below 0°C.
• A spontaneous process occurs without any external energy input. 

Explanation

 A buffer is a solution that resists change in its pH. 

A buffer solution is composed of a weak acid and its conjugate base (or a weak base and its conjugate acid).

When a small amount of a strong acid or base is added to a buffer,

The added ions react with the components of the buffer to maintain a relatively constant pH. 

Explanation

If the activation energy is increased, the rate of reaction decreases. 

Activation energy is the minimum amount of energy needed for reactants to overcome the energy barrier and proceed to form products.

A higher activation energy means that fewer molecules have the necessary energy to react, resulting in a slower reaction rate.

Conversely, a lower activation energy means more molecules can overcome the barrier and react faster.