Explanation

A magnetic compass is a device that responds to the presence of a magnetic field by aligning its needle with the direction of the field.

It is a common tool used to detect and measure magnetic fields.

Explanation

Ohm's Law states that the current (I) flowing through a conductor is directly proportional to the voltage (V) applied across it, and inversely proportional to the resistance (R) of the conductor.

Mathematically, this is expressed as: I = V/R Or, V = I × R

This means that as the voltage increases, the current increases, provided the resistance remains constant.

Explanation

The main source of energy in stars is nuclear fusion.

It is the process of combining atomic nuclei (usually hydrogen nuclei) to form a heavier nucleus, releasing vast amounts of energy in the process.

This energy is what makes stars shine.

Explanation

Ultrasound has several medical applications, including:

• Pre-natal scanning
• Diagnostic imaging
• Cancer treatment

In industry, ultrasound is used for:

• Cleaning and deburring
• Welding and bonding
• Non-destructive testing

Explanation

The work done on a unit charge against an electric field intensity is called electric potential.

It is also known as voltage or potential difference.

It is measured in volts (V) and represents the energy transferred per unit charge.

Electric potential (V) = Work done (W) / Charge (Q)

V = W / Q

Explanation

X-rays are a type of electromagnetic radiation that are commonly used in radiotherapy to destroy cancer cells.

They have enough energy to penetrate deep into tissue and damage the DNA of cancer cells, slowing their growth or killing them.

Explanation

Oscillations are damped due to the presence of frictional force.

Frictional force opposes motion and converts some of the kinetic energy into heat energy, causing the oscillations to decay over time.

There are three main types of frictional force that can cause damping:

• Viscous damping (e.g., air resistance, water resistance)
• Coulomb damping (e.g., friction between surfaces)
• Internal damping (e.g., within the material itself)

Explanation

Dentists use concave mirrors to illuminate inaccessible places in the tooth.

The concave shape of the mirror allows it to reflect light and images from small, hard-to-reach areas.

Such as the back of the mouth or between teeth.

Explanation

When a wave passes from one medium to another, its frequency remains unchanged.

However, its speed, wavelength, and direction may change.

Explanation

Mass is not a characteristic of a wave.

The characteristics of a wave include:

• Amplitude (the maximum displacement of the wave from its equilibrium position)
• Period (the time taken by the wave to complete one oscillation)
• Velocity (the speed at which the wave travels)
• Wavelength (the distance between two consecutive points on the wave that are in phase)
• Frequency (the number of oscillations per unit time)