Physics

Mass is defined as the amount of matter in an object, distinguishing it from volume, density, or space. Therefore, the correct answer is Mass.

Conductors are substances that allow electric current to pass through them easily due to the presence of free electrons. Inductors are components that store energy in a magnetic field, insulators prevent current flow, and wires are physical conductors but the best general term is 'Conductors'.

Jabir bin Hayan is widely regarded as the father of chemistry due to his pioneering work in alchemy and chemical processes, laying the foundation for modern chemistry. The other options are notable scholars but not credited with founding chemistry.

Marie Curie is the only woman scientist who has won the Nobel Prize twice, once in Physics (1903) and once in Chemistry (1911).

Seismic waves generally increase in velocity when they enter the Earth's mantle due to the higher density and rigidity of mantle materials compared to the crust. This causes the waves to travel faster through the mantle.

Dr. Abdul Qadeer Khan obtained his degree in physics from the Catholic University of Leuven in Belgium, not Karachi. Therefore, option B is correct.

LED stands for Light Emitting Diode, which is a semiconductor device that emits light when an electric current passes through it. This is the widely accepted and correct full form of LED.

LASER stands for 'Light Amplification by Stimulated Emission of Radiation,' which accurately describes the physical process behind laser operation.

A microphone's primary function is to convert sound waves into electrical signals or digital data, enabling sound to be recorded, transmitted, or processed. Options A, C, and D describe functions unrelated to microphones.

A transistor is a semiconductor device used to amplify signals while preserving the original signal's shape. It increases the power of incoming signals, making it fundamental in electronic circuits. The other options are either incorrect or less specific for this function.

Vacuum tubes in electronic devices were replaced by transistors because transistors are smaller, more reliable, consume less power, and generate less heat compared to vacuum tubes.

The Doppler effect occurs for any type of wave when there is relative motion between the source and the observer. It applies to both sound waves and light waves, causing a shift in frequency or wavelength.

A silence zone occurs due to destructive interference, where two sound waves of the same frequency and opposite phase cancel each other out, resulting in a reduction or absence of sound.

An ideal insulator does not allow any current to pass through it, which means its resistance is infinitely large. Therefore, the resistance of an ideal insulator is infinite.

Resistivity is a material property and does not depend on the shape or size of the material. Cutting the wire changes its length and resistance but not its resistivity, which remains the same for each part.

A superconductor has zero electrical resistance below its critical temperature, allowing current to flow without energy loss. This is a fundamental property distinguishing superconductors from normal conductors.

Momentum is defined as the product of an object's mass and its velocity, so it depends on both the mass and the velocity of the body.

When two identical traveling waves are superimposed, their velocities do not change because wave velocity depends on the medium and wave properties, not on superposition. Therefore, the resultant wave's velocity remains unchanged.

The typical audible beat frequency that a human ear can perceive is around 7 Hz, as beats are perceived when two close frequencies interfere, producing a fluctuation in sound intensity at the difference frequency. This is within the range humans can detect as beats.

Sodium lamps emit light that is nearly monochromatic, primarily at the yellow wavelength (around 589 nm), making them close to monochromatic sources. Other options like fluorescent tubes and neon lamps emit multiple wavelengths, so they are not nearly monochromatic.

The formula for the distance covered by a body starting from rest under constant acceleration a in time t is s = (1/2) a t². Option A, written as at2/2, correctly represents this formula.

When electrical appliances are connected in parallel, each appliance receives the same potential difference (voltage) across it, but the current through each appliance can be different depending on its resistance. This ensures that each appliance operates independently at the same voltage.

The terminal potential difference becomes zero when the circuit conditions lead to no potential drop across the terminals, such as in a short-circuited ideal case where current is very high and terminal voltage drops to zero. Therefore, the correct answer is 0 V.

In an inelastic collision, kinetic energy is not conserved because some energy is transformed into other forms like heat or deformation. However, the total momentum of the system remains conserved as long as no external forces act on it.

Water surface waves produced by a vibrating pencil are transverse waves because the water particles move perpendicular to the direction of wave propagation. While the waves are periodic due to the regular vibration, the question asks specifically about the type of wave, which is transverse.