Explanation

In longitudinal waves, the particles of the medium move back and forth in the same direction as the wave travels.

This results in compressions and rarefactions within the medium.

Explanation

Radio waves are used for sending sound waves over large distances.

They are capable of transmitting signals over long ranges.

This making them ideal for communication systems like radio and television.

Explanation

• When the rectangular piece of wood is kept in position A.
• Its entire weight is concentrated on a smaller area, resulting in maximum pressure on the table.

Explanation

The becquerel (symbol: Bq) is the SI unit of radioactivity

It is defined as one nuclear disintegration per second 1

it officially replaced the curie (Ci), the unit in the superseded cgs system, in 1975.

Explanation

A movable pulley decreases the amount of input force needed to lift a load.

By allowing the user to apply force over a longer distance.

Explanation

• The Sun is approximately 330,000 times more massive than the Earth.
• It means it has a mass of about 1.989 x 10^30 kilograms.
• The Earth has a mass of about 5.972 x 10^24 kilograms.

Explanation

• Increasing the weight is not a way to reduce friction.

Ways to reduce friction:

• Smoothing and polishing surfaces
• Reducing contact area
• Using oil and lubricants
• Using ball bearings and rollers

Explanation

• An open circuit provides an incomplete path for the current to flow through.
• As the circuit is broken or disconnected, preventing electricity from flowing.

Explanation

• A pulley system is commonly used to raise and lower flags.
• As it allows for a change in direction of the force and makes it easier to lift the flag to a higher position.

Explanation

• The rate of cooling of a body is typically faster at higher temperatures and slows down as the temperature difference between the body and its surroundings decreases. This behavior is governed by Newton's law of cooling.
• Given that the body cools from 90°C to 80°C in 5 minutes, we can infer that the rate of cooling will be slower when the temperature difference is smaller, such as when cooling from 70°C to 60°C.