Electromagnetic Spectrum

Any surface that can reflect light to form an image of an object is a _______.

• mirror

• window

• lens

• screen

Answer explanation

A mirror is a surface that reflects light to create a clear image of an object. Unlike windows, lenses, or screens, mirrors specifically focus on reflection, making them the correct choice for this definition.

When light shines onto a smooth surface, the light bounces off in the _______ direction.

• opposite

• parallel

• perpendicular

• random

Answer explanation

When light hits a smooth surface, it reflects at an angle equal to the angle of incidence, which can be described as bouncing off in the opposite direction. Thus, the correct answer is 'opposite'.

When light bounces off a rough surface it goes in _______ directions.

• many

• one

• none

• two

Answer explanation

When light hits a rough surface, it scatters in many directions due to the uneven texture. This scattering results in multiple angles of reflection, making 'many' the correct answer.

A surface that curves inward and makes things close to it look larger is _______.

• concave

• convex

• flat

• irregular

Answer explanation

A surface that curves inward is called concave. This shape magnifies objects close to it, making them appear larger, unlike convex surfaces which curve outward.

A surface that curves outward and makes things look smaller is _______.

• convex

• concave

• flat

• irregular

Answer explanation

A surface that curves outward is called convex. Convex surfaces make objects appear smaller because they spread light outward, creating a diminishing effect on the size of reflected images.

A lens is a piece of glass or other transparent object that refracts light and produces an image.

• True

• False

Answer explanation

A lens indeed refracts light and produces an image, confirming that the statement is true. Therefore, the correct answer is True.

Light is the only electromagnetic wave that is visible to the human eye.

• True

• False

Answer explanation

True. Light is the only part of the electromagnetic spectrum that is visible to the human eye, while other electromagnetic waves, like radio waves and X-rays, are not visible.

Electromagnetic waves travel at different speeds.

• True

• False

Answer explanation

Electromagnetic waves travel at the speed of light in a vacuum, approximately 299,792 kilometers per second. While they can slow down in different media, their speed in a vacuum is constant, making the statement false.

Radar and cellular phones use microwaves.

• True

• False

Answer explanation

The statement is true because both radar systems and cellular phones operate using microwaves, which are a type of electromagnetic radiation. This allows them to transmit and receive signals effectively.

Radio waves can be used in medicine, art, and engineering. (True or False)

• True

• False

Answer explanation

The statement is False because while radio waves are used in medicine (e.g., MRI) and engineering (e.g., communication), their application in art is not significant or widely recognized.