States of Matter

The human body is approximately 60% water by weight. 3/5 equals 60%, which is the accepted scientific average. Water is distributed in cells, blood, and tissues throughout the body.

Water does expand when it cools from 4°C to 0°C (ice is less dense than liquid water). All metals contract when cooled due to reduced thermal vibration of atoms. Option B is nonsense - 'electrocuted' is not a thermal process. Option D is false - gases expand when heated (Charles's Law).

To answer this question, the user needs to know the definition of the term "sprue." A sprue is a passage or channel that allows molten material to flow into a mold during casting.

Now, let's go through each option and explain why it is right or wrong:

A. Outflow: This option is incorrect because a sprue is not a passage for outflow. Instead, it is a passage for inflow of molten material.

B. Smooth flow: This option is incorrect because a sprue is not a passage for smooth flow. It is specifically designed to allow controlled and directed flow of molten material into a mold.

C. Inflow: This option is correct. A sprue is a passage or channel that allows molten material to flow into a mold during casting. Thus, option C is the correct answer.

D. Solidification of the molten material: This option is incorrect because a sprue is not related to the solidification of the molten material. Instead, it is related to the initial introduction of molten material into the mold.

The Answer is: C

According to Archimedes' principle, ice floats because it displaces a volume of water equal to its mass. When ice melts, it becomes exactly that amount of water, so the total volume remains unchanged and the water level stays the same. This is true regardless of the ice cube's shape or size, as long as it's floating.

At the critical pressure, a gas can condense into a liquid. The critical point represents the highest temperature and pressure at which a gas can be liquefied. Above this point, the gas and liquid phases become indistinguishable (supercritical fluid).

The correct answer is D because 'blood is thicker than water' is a well-known proverb meaning family bonds are stronger than other relationships. Mud, curd, and soup don't fit this traditional saying.

A Remembrall is a glass ball that fills with white smoke when its owner has forgotten something. The white smoke serves as a visual reminder that there's something important they've failed to recall.

Water (H₂O) is a chemical compound made of hydrogen and oxygen atoms, not a chemical element. Elements contain only one type of atom (like oxygen or hydrogen alone), while compounds consist of two or more different elements chemically bonded.

Hydrofluoric acid reacts with silicon dioxide in glass, forming silicon tetrafluoride and water. This makes it unique among acids and is why HF must be stored in plastic containers.

The name hydrogen comes from the Greek words hydro meaning water and genes meaning forming or creator, literally translating to water-forming. This name was chosen because when hydrogen burns in air, it produces water as the product (2H2 + O2 → 2H2O). The other options are incorrect - hydrogen is a naturally occurring element, not artificial, has no connection to bringing light, and is actually one of the most abundant elements in the universe.

Under standard atmospheric pressure, the melting point of ice and freezing point of water both occur at 0°C (32°F). These are phase transition temperatures at which ice and liquid water coexist in equilibrium.

When the glass is whirled in a circular path, the flame points toward the center due to inertia. The more massive gases in the flame have greater inertia and resist the circular motion more than the lighter glass and air, causing them to lag inward relative to the center of rotation.

The brain is approximately 75-78% water by weight. While 80% is commonly cited in older sources, modern measurements place it closer to 75-78%. However, 80% is the best available approximation among these options.

Dosa batter is a liquid (semi-liquid) that becomes solid when heated on a griddle. This is another trick question - most liquids (mercury, petrol, water) don't turn solid on heating. The chemical and physical changes during cooking transform the liquid batter into a solid dosa. 'Hydrogen oxide' is just water's chemical name (H2O).

Heavy water is D2O (deuterium oxide), where the hydrogen atoms are replaced by deuterium, a heavier isotope of hydrogen. Option A is correct.