Who proposed pulsating theory?
Arthur Eddington
What is the meaning of pulsating theory?
: a theory that explains the peculiar features of such stars as the Cepheid variables by assuming an expansion and contraction of the star as a whole in a regular periodic pulsation.
Why is the Big Bang The most accepted theory?
The best-supported theory of our universe’s origin centers on an event known as the big bang. This theory was born of the observation that other galaxies are moving away from our own at great speed in all directions, as if they had all been propelled by an ancient explosive force.
Who proposed pulsating universe theory?
The pulsation theory was first proposed as a possible explanation as early as 1879, was applied to Cepheids in 1914, and was further developed by Arthur Eddington in 1917–18.
What does pulsating mean?
intransitive verb. 1 : to throb or move rhythmically : vibrate. 2 : to exhibit a pulse or pulsation : beat.
What is the difference between steady state theory and pulsating theory?
Steady State Theory discusses that the universe has always been there and will always be present. Oscillating Universe Theory discusses that the universe is expanding and will contract once all the energy after the Big Bang is used up. The collapsing of the universe will then lead to the formation of a new universe.
What is the similarities of steady state and oscillating theory?
The Big Bang theory was the explosive beginning of our universe. The oscillating theory states that our universe can be one of many universes. The steady-state theory is the idea that the universe has to always have the same density which means that there constintly has to be new elements.
What is steady state theory?
Steady-state theory, in cosmology, a view that the universe is always expanding but maintaining a constant average density, with matter being continuously created to form new stars and galaxies at the same rate that old ones become unobservable as a consequence of their increasing distance and velocity of recession.
Who proposed pulsation theory in Ascent of SAP?
J.C. Bose
What is the path of ascent of sap?
The ascent of sap in the xylem tissue of plants is the upward movement of water and minerals from the root to the upper part of the plant body. Xylem is a complex tissue consisting of living and non-living cells.
What is transpiration pull theory?
A transpiration pull could be simply defined as a biological process in which the force of pulling is produced inside the xylem tissue. This force helps in the upward movement of water into the xylem vessels. In this process, loss of water in the form of vapours through leaves are observed.
What is ascent of sap give the most accepted theory of ascent of sap?
Most accepted theory of ascent of sap is transpiration pull theory. Upward conduction of water in the form of a dilute solution of minerals ions (sap) from roots to aerial parts is called ascent of sap.
What are the factors that influence ascent of sap?
Factors affecting ascent of sap
- Water movement is regulated by root pressure and transpiration.
- High temperature, atmospheric pressure, wind velocity and low atmospheric humidity influence the ascent of sap as that of transpiration.
- Soil water deficit also decrease the ascent of sap indirectly by influencing the absorption of water.
How does ascent of sap takes place at night in the absence of transpiration?
At night, when stomata shut and transpiration stops, the water is held in the stem and leaf by the adhesion of water to the cell walls of the xylem vessels and tracheids, and the cohesion of water molecules to each other. This is called the cohesion–tension theory of sap ascent. Figure 1.
Which helps in ascent of xylem sap?
Properties of water which help in the movement of ascent of sap are as follows: Mutual attraction between water molecules. This property is called cohesion. Attraction of water molecules to polar surfaces such as the surface of tracheary elements.
What is called Ascent of SAP?
The upward movement of water from the root to aerial parts of the plant body is called ascent of sap or often called translocation of water. Class-10 » Science. 98 Qs. Ascent of sap is the movement of water and minerals from the roots to the aerial parts of the plant through xylem tissue.
How does Imbibition help in Ascent of SAP?
Imbibition : It is the phenomenon in which colloidal particles attract a large amount of water. This also adds up in the overall process of ascent of xylem sap.
How does capillarity of xylem help in Ascent of SAP?
Capillary action along with the root pressure, the ascent of sap is mainly due to passive forces that develop within the plant, due to certain environmental factors that act upon the plant. tracheids and vessels of the xylem behave as capillary tubes. Ascent of sap is partly due to the capillarity of these tissues.
Which of the following is not responsible for Ascent of SAP?
So, the correct answer is ‘Pressure of tracheary elements’.
What is capillarity in Ascent of SAP?
Capillarity Theory: It is given by Boehm (1809). According to this theory, water is translocated because water molecules adhere to the surfaces of small, or capillary, tubes. This adhesion causes water to somewhat creep upward along the sides of xylem elements.
What is ascent of SAP class10?
Answer: Absorbed water from the soil also contains dissolved minerals (nitrates, phosphates, etc.) and hence it is called sap. This sap moves upwards due to the ‘transpiration pull’ developed in the xylem elements. Thus, transportation of sap from roots to the leaves at the top is called ascent of sap.
What are the three steps involved in the process of ascent of sap?
Answer. Answer: The theory states that transpiration pull or tension, cohesion property of water, and hydration of the cell walls (i.e., adhesion) are collectively responsible for the ascent of sap.