Daily NEET MCQ- June 13, 2022 - NEET MCQ

The reason for the phase to change by π is that the boundary displacement should be zero because it is rigid & by principle of superposition it is only possible if the reflected wave differs by a phase of π.

At the free surface reflected wave suffers no phase change.
Only the direction of wave propagation gets reversed.
So, the equation will be y = 2sin(4x+3t).

The amplitude in a standing wave is given by Asin(kx).
Node is a point where amplitude is zero and antinode is a point where amplitude is maximum.
For a node, sin(kx) = 0
kx = 2nπ OR (2π/λ)x = nππ
x = nλ/2.
For an antinode, sin(kx) = 1
kx = (2n+1)π/2
(2π/λ)x = (2n+1)π/2
x = (2n+1) λ/4.
∴ node is at λ/2, λ, 3λ/2 …
& antinode at λ/4, 3λ/4, 5λ/4 …
∴ minimum distance = λ/2 – λ/4 = λ/4.

Occlusion is nothing but the absorption of hydrogen at a metal surface which is a primary cause of reduction, hydrogenation, etc. As the temperature increases, occlusion decreases i.e. they are dependent on each other.

When in the hydrogen molecule, the nucleus spins are in the same direction, it is known as orthohydrogen. When the spins are in the opposite direction, it is known as parahydrogen. At room temperature hydrogen consists of 75% ortho and 25% para hydrogens.

Nascent hydrogen is the hydrogen is freshly obtained from a chemical reaction and is more reactive than normal hydrogen comparatively as it is not stable. The activity of nascent hydrogen depends upon the reaction by which, it is obtained.

During the process of respiration, oxygen is utilised and carbon-dioxide, water and energy are released as products. The combustion reaction requires oxygen.

The first cells on this planet lived in an atmosphere that lacked oxygen. Even among present-day living organisms, we know of several organisms that are adapted to anaerobic conditions.

In any case, all living organisms retain the enzymatic machinery to partially oxidise glucose without the help of oxygen. This breakdown of glucose to pyruvic acid is called glycolysis.

Glycolysis occurs in the cytoplasm of the cell and is present in all the living organisms. In anaerobic organisms, it is the only process in respiration.