Explanation

Given kinetic energy (K.E) = 1 J and mass (m) = 1 kg:

K.E = ½mv²

1 = ½ * 1 * v²

v² = 2

v = √2 ≈ 1.414

The correct answer is 1.4 m s⁻¹.

Explanation

Work done (W) is calculated as:

W = F * d * cos(θ)

where F is the force, d is the displacement, and θ is the angle between the force and displacement.

For work done to be zero, cos(θ) needs to be 0, which happens when:

θ = 90°

Explanation

Steam causes more severe burns than boiling water because it carries latent heat of vaporization.

It releases extra energy when it condenses on the skin.

Explanation

Radiation: Gas heaters emit infrared radiation that heats up objects and people directly.

Convection: The heated air rises and circulates around the room, warming it through convection.

Explanation

A washing machine uses an electric motor to produce mechanical motion for spinning and agitating clothes.

This is a clear example of converting electrical energy into mechanical energy.

Explanation

According to Coulomb's Law, the force between two charges decreases as the square of the distance between them increases.

Formula: F ∝ 1/r², where r is the distance between the charges.

Explanation

Cornstarch and water form a non-Newtonian fluid called oobleck, which:

• Acts like a liquid when moved slowly
• Acts like a solid when force is applied

Explanation

A vacuum flask is designed to minimize heat transfer by radiation, conduction, and convection to keep the contents hot or cold.

It uses a vacuum between two walls to prevent heat loss through conduction or convection, and its reflective surface helps reduce heat transfer by radiation.

Explanation

A diode allows current to flow in only one direction — from anode (positive) to cathode (negative).

It acts as a one-way valve for electric current, conducting only when forward-biased (positive to anode, negative to cathode).

Explanation

Iron magnets are temporary because they lose magnetism quickly when the external magnetic field is removed.

Steel magnets retain their magnetism for a long time, making them permanent magnets.