Explanation: Tuberculosis (TB) is not a viral disease; it is caused by a bacterium called Mycobacterium tuberculosis. In contrast, Polio, Swine flu, and Hepatitis are viral diseases caused by different types of viruses.

Explanation: Uranium-235 (U-235) is the isotope used for the production of atomic energy because it is fissionable. When bombarded with neutrons, U-235 undergoes nuclear fission, releasing a large amount of energy along with additional neutrons, which sustain the chain reaction in nuclear reactors and atomic bombs.

Methane (CH₄) is not an allotrope of carbon. It is a chemical compound made up of one carbon atom and four hydrogen atoms. In contrast, allotropes are different structural forms of the same element in the same physical state. Carbon has several allotropes, including diamond, graphite, and fullerene (C-60), which differ in atomic arrangement and physical properties.

Other options (for context)

• Diamond: An allotrope of carbon where each carbon atom is tetrahedrally bonded to four others, making it extremely hard.
• Graphite: An allotrope of carbon with layers of hexagonally arranged atoms; good conductor of electricity.
• C-60 (Fullerene): A spherical allotrope of carbon consisting of 60 atoms arranged like a soccer ball.

Ocean Thermal Energy (OTE) is produced due to the temperature difference at different levels in the ocean. The surface water is warmer because it absorbs sunlight, while the deeper layers remain cold. This temperature gradient is used to run a heat engine that generates electricity — a process known as Ocean Thermal Energy Conversion (OTEC).

• Tides: Related to gravitational pull, not temperature.
• Pressure difference: Exists but not used for energy generation.
• Waves: Used in wave energy systems, not OTEC.

The gravitational force of the Earth is maximum at the poles and minimum at the equator. This happens because the Earth is not a perfect sphere; it is slightly flattened at the poles and bulged at the equator due to its rotation. The distance from the center of the Earth to the poles is slightly less than that to the equator, resulting in a stronger gravitational pull at the poles.

Other options (for context)

• At equator: Gravity is slightly weaker because of the Earth's bulge and centrifugal force due to rotation.
• At tropic of cancer: Gravity here is intermediate, not maximum.
• At tropic of Capricorn: Same as the Tropic of Cancer — gravity is moderate, not maximum.

Explanation: Unwanted or unsolicited e-mails sent in bulk are called spam. These messages often contain advertisements, phishing links, or malware. They clutter inboxes and can pose security risks. The term “spam” originated from a comedy sketch by Monty Python, where the word was repeatedly used, much like unwanted messages.

A rocket functions based on Newton’s Third Law of Motion, which states that “for every action, there is an equal and opposite reaction.” The rocket expels gases downward at high speed (action), and in response, the rocket is propelled upward (reaction). This principle enables space rockets to move even in the vacuum of space where no air resistance exists.

• Newton’s First Law: Deals with inertia, not propulsion.
• Newton’s Second Law: Explains force and acceleration but doesn’t directly describe rocket thrust.

Explanation: Respiration is a biochemical process in which food molecules (mainly glucose) are oxidized to release energy in the form of ATP (adenosine triphosphate). This energy is then used for various life processes such as movement, growth, repair, and maintenance. Respiration occurs in all living cells and takes place mainly inside the mitochondria.

Chemical Equation:

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy (ATP)

In contrast, photosynthesis stores energy in glucose molecules, while respiration releases that stored energy for cellular use.

Explanation: Teflon, also known as polytetrafluoroethylene (PTFE), is the polymer used in making non-stick kitchenware. It has a very low coefficient of friction and is resistant to heat and chemicals, which prevents food from sticking to cookware surfaces.