Tag: science & technology

Iron is a metal and conducts heat well, making it a poor insulator. Wood, wool, and feathers trap air and are good thermal insulators used in clothing and construction.

Iron is ferromagnetic and strongly attracted to magnets. Glass, leather, and sodium are not magnetic materials.

When a compressed spring is released, stored elastic potential energy converts to kinetic energy as the spring moves. This is conservation of energy in mechanical systems.

Conductors like metals have low resistance, allowing electric current to flow easily. Insulators have very high resistance that prevents current flow.

A freely suspended magnet aligns with Earth's magnetic field, pointing north-south. This is why compass needles indicate direction. The north pole points toward magnetic north.

A freely suspended magnet aligns with Earth's magnetic field, pointing north-south. This is why compass needles indicate direction. The north pole points toward magnetic north.

Refraction is the bending of light when it passes from one medium to another at an angle, due to the change in light speed. Reflection is bouncing back, convection and radiation are heat transfer methods.

When white light passes through a prism, it disperses into a continuous band of seven colors called a spectrum. This happens because different colors (wavelengths) bend at different angles as they enter and exit the prism. The scientific term for this rainbow-like pattern is 'spectrum', not 'color band' or 'color arc'.

Black holes form when massive stars undergo gravitational collapse, typically triggered by supernova explosions. During a supernova, the core of a massive star collapses inward under its own gravity, forming a region of spacetime with gravity so strong that nothing can escape. Option A correctly identifies supernovae as the primary formation mechanism.

Light travels in straight lines when moving through a uniform medium. This is a fundamental property of light known as rectilinear propagation. We can observe this principle in the formation of sharp shadows - if light didn't travel straight, shadows would always be fuzzy at the edges.