Explanation

Copper, silver, aluminum, gold, steel, and brass are common conductors of electricity.

The most highly conductive metals are silver, copper, and gold

Silver is the first-best conductor of heat.

Copper is the second-best conductor of heat.

Explanation

Velocity is a vector quantity. 

A vector quantity has both magnitude and direction.

Velocity, which describes the rate of change of position in a specific direction, needs both a magnitude (speed) and a direction to be fully defined. 

Vector Quantities: Velocity, momentum, torque, acceleration.

Scalar Quantities: Work, distance, speed, mass.

Explanation

Hazrat Ismael (AS) is called Abu-ul-Arab (Father of the Arabs) because Arab tribes trace their lineage through him.

He settled in Makkah and married into the Jurhum tribe, giving rise to Arab ancestry.

Explanation

A spectrometer is an instrument used to measure the properties of light over a specific portion of the electromagnetic spectrum, especially to analyze line spectra produced by atoms or molecules.

It helps identify elements or compounds by detecting their unique emission or absorption lines in the spectrum.

A spectrometer is an instrument used to measure the wavelength of light (or other electromagnetic radiation) by dispersing it into a spectrum.

It is commonly used to analyze the spectral lines of elements, which correspond to specific wavelengths.

Explanation

X-rays are electromagnetic waves and not charged particles, so they are not deflected by electric or magnetic fields.

They travel in straight lines, affect photographic plates, and have properties of electromagnetic radiation.

Explanation

In simple harmonic motion (SHM), the restoring force is given by:

F = -kx

Where:  

- F is the restoring force  

- k is the spring constant  

- x is the displacement from the equilibrium position  

The restoring force is minimum when displacement x = 0, i.e., at the equilibrium position.

Explanation

Change in momentum = 20 − 5 = 15 kg·m/s

Time = 3 s → Force = 15 / 3 = 5 N

Explanation

The Earth bulges at the equator and rotates, creating a centrifugal force that slightly reduces gravity there.

At the poles, this effect is minimal, so ‘g’ is stronger at the poles than at the equator.

Explanation

An electric generator works on the principle of electromagnetic induction.

Faraday's law states that a changing magnetic flux induces an emf, which is the working principle of generators.

Explanation

Kinetic energy (K) is related to momentum (p) by K = p² / 2m. If momentum increases by 20%, the new momentum p' = 1.2p.

The new kinetic energy K' = (p')² / 2m = (1.2p)² / 2m = 1.44p² / 2m = 1.44K.

The percentage increase in K.E is ((K' - K) / K) × 100 = ((1.44K - K) / K) × 100 = 44%.