PHysics: 3rd 9 weeks Review

Which of the following best describes the wave-particle duality of light?

• Light behaves only as a wave.

• Light behaves only as a particle.

• Light exhibits both wave and particle properties.

• Light is neither a wave nor a particle.

Answer explanation

The correct choice is that light exhibits both wave and particle properties. This duality is fundamental in quantum mechanics, where light can behave like a wave in some experiments and like a particle in others.

Which part of the electromagnetic spectrum has the highest frequency?

• Radio waves

• Microwaves

• Ultraviolet light

• Gamma rays

Answer explanation

Gamma rays have the highest frequency in the electromagnetic spectrum, exceeding that of radio waves, microwaves, and ultraviolet light. This high frequency corresponds to their high energy and penetrating power.

What is the speed of light in a vacuum?

Answer explanation

The speed of light in a vacuum is universally accepted as approximately 3 x 10^8 m/s. This value is fundamental in physics and is crucial for understanding various phenomena, making it the correct choice.

What happens to light when it passes from air into water?

• It speeds up.

• It slows down.

• It maintains the same speed.

• It stops.

Answer explanation

When light passes from air into water, it slows down due to the higher density of water compared to air. This change in speed causes the light to bend, a phenomenon known as refraction.

Which phenomenon is responsible for the bending of light as it passes through different media?

• Reflection

• Refraction

• Diffraction

• Interference

Answer explanation

Refraction is the phenomenon that causes light to bend when it passes from one medium to another, due to a change in its speed. This bending effect is distinct from reflection, diffraction, and interference.

Which of the following is an example of light interference?

• A rainbow

• A prism dispersing light

• Soap bubbles showing colors

• A mirror reflecting light

Answer explanation

Soap bubbles show colors due to light interference, where different wavelengths of light reflect and combine, creating vibrant colors. This phenomenon is distinct from a rainbow, prism dispersion, or mirror reflection.

What is the primary cause of diffraction?

• Light passing through a prism

• Light reflecting off a surface

• Light bending around an obstacle

• Light being absorbed by a material

Answer explanation

The primary cause of diffraction is light bending around an obstacle. This phenomenon occurs when light waves encounter an edge or slit, causing them to spread out rather than travel in straight lines.

Which of the following colors of visible light has the shortest wavelength?

• Red

• Green

• Blue

• Violet

Answer explanation

Violet light has the shortest wavelength among the visible colors, ranging from about 380 to 450 nanometers, while red has the longest. Therefore, the correct answer is violet.

What is the principle behind the operation of a laser?

• Spontaneous emission

• Stimulated emission

• Absorption

• Reflection

Answer explanation

The principle behind laser operation is stimulated emission, where an incoming photon stimulates an excited atom to emit a second photon, resulting in coherent light. This process is fundamental to laser technology.

Which of the following best describes the photoelectric effect?

• Emission of electrons when light hits a metal surface

• Absorption of light by a metal surface

• Reflection of light from a metal surface

• Refraction of light through a metal surface

Answer explanation

The photoelectric effect refers to the emission of electrons from a metal surface when it is exposed to light. This phenomenon demonstrates the particle nature of light, where photons can transfer energy to electrons.