Daily NEET MCQ- April 25, 2022 - NEET MCQ

The work done (W) is given by;

W = Force x Displacement

The area enclosed by the curves in the graph shown gives the work done;

Enclosed area = [(1/2) x 4 x 10] + (4 x 10) + [(1/2) x 4 x 10]

= 80 Nm

= 80 J.

Length (l) = 5 m

Height = Displacement = 5 x sin30

= 5 x (1/2)

= 2.5

Force on object = m x g

= 10 X 10

= 100 N

Work = Force x Displacement

= 100 x 2.5

= 250 Joules.

According to the Arrhenius concept of acids and bases, an acid is a chemical substance which dissociates in aqueous solution to give hydrogen ions or hydronium ions. Therefore HCl is an Arrhenius acid.

According to the bronsted concept of acids and bases, an acid that is a Proton Donor is proton genic and a base that is a Proton acceptor is protophilic, while an amphoteric substance is both base and acid.

As per the conjugate pairs in the bronsted concept of acid and bases, strong acid has a weak conjugate base and weak acid has a strong conjugate base. The strong base has weak conjugate acid and the weak base has strong conjugate acid.

Light and temperature are among the most important factors affecting transpiration externally. Number of stomata, canopy structure and water status of plant are internal factors regulating transpiration.

% open stoma is an important determinant of the loss due to transpiration. If less number of stomata is open, less transpirative loss will occur. Temperature, humidity and wind speed affect transpiration externally.

In plants, capillarity is aided by the small diameter of the xylem elements, i.e., the tracheids and vessel elements. Capillarity is the ability to rise in thin tubes. Cohesion is mutual attraction between molecules of H2O. Adhesion is attraction of water molecules to the surfaces of tracheary elements. Tensile strength is ability to resist a pulling force. Adhesion, cohesion and tensile strength are properties of xylem which enables the ascent of xylem sap.

Thin outer wall bulges out due to change in turgidity of guard cells during the shift from night to day. This leads to thick inner wall being pulled outside by the outer wall, thereby forming crescent shape.

Transpiration is the loss of water in the gaseous phase from the leaves. It is a necessary evil. It might be a major cause of loss of water but it is the driving force for ascent of xylem sap, therefore, conduction of water and minerals. It creates pressure in xylem which can allow water conduction up to 130m height. Transpiration is a pulling force while root pressure is a pushing force.