Basic Physics and General Science Quiz

By definition, 1 calorie (small 'c') is the amount of heat energy required to raise the temperature of 1 gram of water by 1°C. This is different from a Calorie (capital 'C'), which equals 1000 calories and is used in nutrition.

The speed of sound in air at 25°C is approximately 346 m/s. Among the options, 330 m/s is the closest approximation. The speed of sound in air increases with temperature and is roughly 331 m/s at 0°C, increasing by about 0.6 m/s per degree Celsius.

The SI unit of electric current is Ampere (misspelled here as 'Amphere'). Farad measures capacitance, Ohm measures resistance, and Mho measures conductance.

A magnifying glass uses a convex lens, which is thicker at the center and converges light rays to create a magnified image. Concave lenses diverge light and make objects appear smaller.

The thin wire inside an electric bulb that glows when current passes through it is called the filament. It's typically made of tungsten due to its high melting point.

A gold leaf electroscope detects electric charge - when a charged object touches it, the gold leaves repel each other. Ammeters measure current, thermometers measure temperature.

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.

Metals expand when heated because increased thermal energy causes atoms to vibrate more vigorously and push apart. Conversely, when metals cool, the atoms lose energy and settle closer together, resulting in contraction. This thermal expansion and contraction is a fundamental property of metals used in applications like bimetallic strips and thermometers.

Bats produce ultrasonic sounds above 20 kHz for echolocation, which is beyond the upper frequency limit of human hearing (approximately 20 kHz for infants, decreasing with age). These high-frequency cries bounce off objects and return as echoes, allowing bats to navigate and hunt in complete darkness. The statement is scientifically accurate.

Stars generate energy through nuclear fusion, where lighter nuclei (primarily hydrogen) combine to form heavier nuclei (helium) in the star's core. This process releases enormous amounts of energy because the mass of the products is slightly less than the mass of the reactants - this 'missing' mass is converted to energy according to E=mc². Nuclear fission (splitting heavy nuclei) is not the primary energy source for stars.