General Awareness · Science General

Inventors and Scientific Discoveries

4,616 Questions

This hub provides questions related to great inventors and their scientific discoveries. It covers the inventors of the telephone, radio, and microchips, alongside Nobel Prize winners. These facts are crucial for the general awareness section of major competitive exams.

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Inventors and Scientific Discoveries Questions

Multiple choice botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

The gridling or ringing experiment to prove that the water moves through the xylem vessels was performed by

  1. Stocking

  2. Malpighi

  3. Molisch

  4. Askenasy

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This experiment was introduced by Malpighi in 1675. It involves the removal of a ring of bark (girdle), that is, all tissues outside the vascular cambium. Thus, the correct answer is (B).

Multiple choice botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

Sir J.C. Bose proposed a theory of ascent of sap known as 

  1. Pulsation theory

  2. Transpiration pull theory

  3. Relay pump theory

  4. Capillary force theory

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Sir J.C. Bose proposed a theory of ascent of sap known as pulsation theory. The pulsation theory states that water is absorbed by the plants due to the metabolic activity of living cells which are in constant state of rythmatic pulsation. But it was not accepted as water can be passively absorbed by the roots even the cells were dead.

So, the correct answer is option A.

Multiple choice botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

Relay pump theory of ascent of sap was proposed by

  1. Bose

  2. Godlewski

  3. Westermaler

  4. Von sachs

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Godlewski proposed relay pump theory to explain ascent of sap. According to him there was a rhythmic change in the osmotic pressure of the living cells of xylem parenchyma and medullary rays, which brought about a pumping action of water in an upward direction.

The tracheids and vessels acted as water reservoirs. Janse supported Godlewski and showed that if the lower portion of branch was killed, the leaves above were affected.


Multiple choice botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

Capillary force theory to explain ascent of sap was proposed by

  1. Boehm

  2. Sachs

  3. Jamin

  4. None of the above

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Capillarity TheoryIt 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. In glass tubes this upward movement is visible as the curved or crescent-shaped (concave) meniscus. However, it was shown that capillarity (or capillary rise) alone in tubes of similar diameter as that of a xylem element raises water less than 1 meter.

Hopkins (1999) explained that the relationship between the rise of water in a capillary tube and the size of the tube is inversely proportional. This means that the thinner is the tube, the higher will be the rise of water.

Multiple choice botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

Ringing experiment to explain ascent of sap path was first done by

  1. Hartig and Malpighi

  2. Dixon and J. C. Jolly

  3. Godlewski and J. C. Bose

  4. Stephen hales and Boehm

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Downward translocation of the organic solutes takes place through phloem. This can be proved by the ringing experiment. Ringing experiment was carried by Hartig, Malpighi and Stephen Hales.
They took a branch with leaves immersed in beaker which is filled with water. Now remove all the tissues which are present above the xylem [cortex, cambium and phloem]. Now placed this experiment in a suitable environment for 2 - 3 days. Then they observed that leaves did not wilt. This experiment makes it clear that water moves up only through vessels and tracheids of the xylem. 
Ringing [girdling] experiment has been done only in dicotyledons because their vascular bundles lies in a ring. While vascular bundles are scattered in monocotyledons, so that this experiment can not be possible.

Multiple choice botany water absorption and ascent of sap in plants apoplast and symplastic pathway transport of water in plants water transport

The imbibition theory for the ascent of sap was suggested by

  1. Sir J. C. Bose

  2. Strassburger

  3. Sachs

  4. Dixon and Jolly

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Imbibitions theory was proposed (1868) and supported by Sachs (1878). According to this theory the ascent of sap occurs due to imbibitonal activity of the cell walls of the xylem elements.

This theory is discarded as it has been experimentally found that water rises up through the lumen of the xylem and not through the walls.

Multiple choice physics behaviour of perfect gas and kinetic theory of gases degree of freedom: law of equipartition of energy law of equipartition of energy law of equipartition of energy and mean free path

The law of equipartition of energy was given by :

  1. Claussius

  2. Maxwell

  3. Boltzmann

  4. Carnot

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The law is given by Claussius which states that for any dynamical system in a thermal equilibrium, the total energy is equally divided among the degrees of freedom.

Multiple choice physics electric current and its effects electric fuse electrical fuse and mcb fuse

......... suggested that the slips should be marked with load lines

  1. Samuel Plimsoll

  2. Einstein

  3. Newton

  4. Archimedes

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Fuse should be connected to live / phase wire o fthe circuit. If it is connected to neutral wire , the fuse will melt when excess current flows, but the appliance will still be connected to high potential through live wire. Thus, if a person touches the appliance, he receives shock. 
Hence, choice is (3) 

Multiple choice biology transport in mammals regulation of the activity of heart drug, tobacco and alcohol consumption community health and hygiene

Who was first to record EEG of man?

  1. Hans Berger

  2. Galileo Galilei

  3. Willem Einthoven

  4. Sanctorius

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Electroencephalography (EEG) is the recording of electrical activity along the scalp. EEG measures voltage fluctuations resulting from ionic current flows within the neurons of the brain. German physiologist and psychiatrist Hans Berger recorded the first human EEG in 1924. 

Multiple choice biology transport in mammals regulation of the activity of heart drug, tobacco and alcohol consumption community health and hygiene

A drug called reserpine was discovered by

  1. Jal Vakil

  2. Paul Ehrlich

  3. Hansen

  4. Alexander Wood

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Reserpine is an indole alkaloid, antipsychotic and antihypertensive drug that has been used for the control of high blood pressure.
Rustom Jal Vakil was the first to pioneer the use of resperine to control hypertension.
Thus, the correct answer is option (A), 'Jal Vakil'.

Multiple choice biology transport in mammals regulation of the activity of heart drug, tobacco and alcohol consumption community health and hygiene

Stethoscope was invented by

  1. René Laennec

  2. Wilhelm Roentgen

  3. Edward Jenner

  4. Joseph Lister

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation
Stethoscope was invented by Rene Laennec. It is a medical device which is mainly used to hear the sound of heart, intestine, blood flow of the arteries and veins.
Wilhelm Roentgen discovered x rays.
Edward Jenner developed the first vaccine for smallpox.
Lister successfully introduced carbolic acid to sterilize surgical instruments and wounds.
So, the correct answer is option A.
Multiple choice botany photosynthesis cam cycle cam plants photosynthetic cycle

Who coined the term CAM?

  1. Benson

  2. Ranson and Thomas

  3. Benson and Thomas

  4. Arnon

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Ranson and Thomas coined the term CAM (Crassulacean Acid Metabolism)  in 1940. CAM pathway is a carbon fixation pathway that evolved in some plants as an adaptation to arid conditions. In a plant using full CAM, the stomata in the leaves remain shut during the day to reduce evapotranspiration, but open at night to collect carbon dioxide.

Multiple choice bio-chemistry biological molecule lipids and their function some biomolecules lipids

Essential fatty acids were discovered by

  1. Evans and Burr

  2. Bloor

  3. Sutherland

  4. Beevers

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Essential fatty acids are those fatty acid which plays an important role in the biological process and they can be metabolized easily. These acts as a fuel rather getting deposited as fat in the body. The human body cannot synthesize essential fatty acids. Alpha-linolenic acid and linoleic acid are the two essential fatty acid. It was discovered by Evans and Burr.

So, the correct answer is option A.

Multiple choice chemistry particle nature, basic units history of atomic model atomic theory of dalton daltons atomic theory

The atom is indivisible was proposed by :

  1. Rutherford

  2. Dalton

  3. Bohr

  4. Einstein

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

John Dalton considered that " all matter is composed of small particle called the atom."
According to Dalton: 
-Atom is the smallest indivisible part of matter which takes part in the chemical reaction.
-Atom is neither created nor be destroyed.