7th Grade Quiz : Light And IT's Properties

Explanation
Transparent materials are those through which light can pass easily, allowing objects to be seen clearly on the other side. These materials have a high degree of transparency, meaning they transmit light without scattering or absorbing it significantly. Examples of transparent materials include glass, water, and air.

Explanation
Translucent materials allow some light to pass through, but the light is scattered in different directions, causing objects to appear blurry. Unlike transparent materials, which allow light to pass through without scattering, and opaque materials, which do not allow any light to pass through, translucent materials strike a balance between the two, allowing some light transmission while still causing distortion and blurriness. Therefore, the correct answer is translucent.

Explanation
Opaque materials are those through which light cannot pass. They do not allow light to pass through them and therefore block the transmission of light. This is in contrast to transparent materials, which allow light to pass through them with minimal or no obstruction, and translucent materials, which allow some light to pass through but scatter it in different directions. Opaque materials are typically solid and do not transmit any light, making them appear dark or non-transparent.

Explanation
Radio waves are a type of electromagnetic radiation with low frequency and low energy. They have a longer wavelength than 30 cm. These waves are commonly used for communication purposes, such as radio and television broadcasting. They are also used in radar systems and wireless communication devices. In contrast, infrared waves have a shorter wavelength and are used for applications such as heat sensing and remote controls. Ultraviolet waves have an even shorter wavelength and are known for their ability to cause sunburn and damage to skin cells. Therefore, the correct answer is radio waves.

Explanation
Infrared waves have a slightly shorter wavelength and higher frequency than light. They are a type of electromagnetic wave that falls between microwaves and visible light on the electromagnetic spectrum. Infrared waves are commonly used in applications such as thermal imaging, remote controls, and communication systems. They are also responsible for the heat we feel from the sun and can be detected by specialized sensors or cameras.

Explanation
Ultraviolet waves have a shorter wavelength than microwaves and longer wavelength than light waves. They are a form of electromagnetic radiation that is invisible to the human eye. Ultraviolet waves have higher energy than visible light and can cause sunburn and skin damage. They are commonly used in sterilization processes and in medical and scientific applications.

Explanation
When light falls on an opaque object, it is not able to pass through it. Instead, the object reflects certain wavelengths of light while absorbing others. The color that we perceive from the object is the color of light that it reflects. Therefore, the correct answer is "reflects".

Explanation
The intensity of light is determined by how much energy it carries. This is because the intensity refers to the amount of power per unit area that the light wave carries. The more energy the light wave has, the greater its intensity will be. Therefore, the correct answer is "how much energy it has".

Explanation
The retina is the structure in the eye that sends signals about what you see to the brain. It contains specialized cells called photoreceptors that convert light into electrical signals. These signals are then transmitted through the optic nerve to the brain, where they are interpreted as visual information. The lens and cornea are responsible for focusing light onto the retina, but they do not directly send signals to the brain. Therefore, the correct answer is retina.

Explanation
Light is a form of energy that travels in the form of waves. These waves are known as electromagnetic waves because they consist of both electric and magnetic fields oscillating perpendicular to each other. This is why light can travel through a vacuum, as it does not require a medium to propagate like mechanical waves. Therefore, the correct answer is electromagnetic.