Explanation

Attrition is the process where rocks and pebbles grind against each other, causing them to wear down.

It occurs mainly in rivers or along the coast due to movement and collision.

Explanation

• The speed of sound in air at 0°C (32°F) is 332 meters per second.

The speed of sound in different materials:

• Air: 332 m/s
• Sea water: 1530 m/s
• Lead: 2160 m/s
• Gold: 3240 m/s
• Brick: 3650 m/s
• Copper: 4760 m/s
• Glass: 5100 m/s
• Aluminium: 6420 m/s

Explanation

Tar is the major component of particulate matter inhaled in cigarette smoke.

It contains several carcinogens.

It is responsible for lung damage.

Explanation

The change in wavelength (Δλ) is given by the formula: Δλ = h/m0c (1 - cosθ), where θ is the scattering angle.

The maximum change in wavelength occurs when cosθ is -1, which happens when θ = 180°.

Explanation

Centripetal force is any force that keeps an object moving in a circular path, directed toward the center of the circle.

Tension in a string, gravitational force (like planets orbiting), and friction (like a car turning) can all provide centripetal force.

Explanation

For a polyatomic gas, Cv is typically 3R, accounting for translational and rotational degrees of freedom.

This value can increase with temperature as vibrational modes become excited, contributing to the specific heat.

Explanation

Let's denote the mass and radius of both objects as M and R, respectively.

For a thin-walled cylinder about its central axis, I_cylinder = MR².

For a solid sphere about its diameter, I_sphere = (2/5)MR².

The ratio is I_cylinder / I_sphere = MR² / ((2/5)MR²) = 5/2.

Explanation

A rectifier is an electrical device that converts Alternating Current (AC) into Direct Current (DC).

It works by allowing current to flow only in one direction using diodes.

Explanation

Spring potential energy is given by U = 1/2kx².

If stretching to distance S gives 10 J, then to stretch to 2S, the energy becomes 1/2k(2S)² = 4×10 = 40 J.

So, additional work =  40−10 = 30 J.

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.