Science, Technology & Engineering Quiz

A 2-stroke engine has only one moving valve - the reed valve or rotary valve that controls fuel intake into the crankcase. Unlike 4-stroke engines with multiple valves (intake and exhaust), 2-strokes use ports in the cylinder wall for exhaust and transfer, controlled by piston position rather than separate valves.

Worm gear and worm wheel systems have their shaft axes positioned at 90 degrees to each other, making them ideal for applications requiring right-angle power transmission with high gear reduction. Spur and helical gears have parallel axes, while double helical gears also maintain parallel shaft alignment.

In the vacuum of space, only radiation can transfer heat since conduction requires physical medium and convection requires fluid motion. Satellites use radiators and thermal coatings to dissipate excess heat and manage temperature extremes. The lack of atmosphere makes both conduction and convection impossible for space-based heat transfer.

Reaming is a finishing operation performed after drilling to achieve accurate hole size and smooth surface finish. Drilling alone produces holes with tolerances of about IT12-IT13, while reaming can achieve IT7-IT9 precision. Slotting creates grooves, facing produces flat surfaces, and neither refines hole diameter like reaming does.

Slotting requires a reciprocating cutting motion perpendicular to the workpiece, which is characteristic of slotting machines or vertical machining centers. A lathe operates with rotational workholding and continuous cutting along the workpiece's surface, making slotting impossible on standard lathes. Turning, knurling, and facing are all standard lathe operations.

The LHC (Large Hadron Collider) tunnel has a circumference of 27 kilometers. This circular tunnel houses the world's largest particle accelerator. The 26 km, 28 km, and 25 km options are not correct measurements.

CERN stands for European Organization for Nuclear Research. This is the correct expansion of the acronym. The options with 'Nuetron', 'Natural', and 'Nuclear particle' are incorrect spellings or additions.

NOTEM is not in the list of LHC experiments. ALICE, ATLAS, and TOTEM are all real LHC experiments. NOTEM appears to be a fictitious name created for this question.

On September 10, 2008, CERN successfully fired the first protons around the entire LHC tunnel circuit in stages. This was a major milestone in the commissioning of the LHC. The first high-energy collisions and lead ion runs came later. The shutdown option is also incorrect.

Hadrons are composite particles made of quarks held together by the strong nuclear force, classified into baryons (three quarks, like protons and neutrons) and mesons (quark-antiquark pairs). Option A incorrectly limits hadrons to just protons, while electrons (option C) are leptons, not hadrons.

Both statements are correct. Hepatitis B is significantly more infectious than HIV (estimated 10-100 times more contagious through blood contact) and is a major risk factor for liver cancer (hepatocellular carcinoma), especially in chronic carriers. The virus causes liver cirrhosis and cancer over decades of chronic infection.

CO causes hypoxia because it has 200-250 times higher affinity for hemoglobin than oxygen, forming carboxyhemoglobin and preventing oxygen transport. Options A, C, and D are incorrect because CO is not converted to CO2, does not destroy hemoglobin structure, and primarily affects oxygen transport at the molecular level rather than the respiratory center in the brain.

The risk of male-to-female transmission of HIV during sexual intercourse is actually higher than female-to-male transmission. Therefore, the statement claiming female-to-male transmission is twice as likely is incorrect.

Statement 1 is correct - India lacks access to affordable clean technologies for renewable energy and emission reduction. Statement 2 is correct - India's R&D funding is limited compared to developed nations. Statement 3 is incorrect - while some polluting industries have moved to India, this is not listed as a primary limitation in climate mitigation discussions; technology transfer and funding are bigger constraints.

Homi Bhabha founded the Tata Institute of Fundamental Research (TIFR) in 1945 with support from J.R.D. Tata. He is also known as the father of the Indian nuclear program. Vikram Sarabhai founded ISRO, and Anil Kakodkar was a later nuclear scientist.

Jagadish Chandra Bose demonstrated plant sensitivity through his pioneering experiments in the early 20th century, using his invention the crescograph to detect plant responses to various stimuli. He showed plants could feel and react to their environment.

A.P.J. Abdul Kalam is known as the Missile Man of India for his pivotal role in developing India's missile technology, including the AGNI and PRITHVI missile series. He was a key figure at DRDO and later became India's President.