Waves and Electromagnetic Spectrum

Flashcards based on lecture notes about waves and the electromagnetic spectrum.

What is the direction of vibration in a transverse wave?

The direction of vibration is perpendicular to the direction of the wave.

Give two examples of transverse waves.

Water waves and light waves.

What is the direction of vibration in a longitudinal wave?

The direction of vibration is parallel to the direction of the wave.

Give an example of a longitudinal wave.

Sound wave.

What is frequency?

The number of complete waves produced per second.

What is the SI unit for frequency?

Hertz (Hz).

How many Hz are in 1 kHz?

1000 Hz

How many Hz are in 1 MHz?

1,000,000 Hz

What are crests?

The highest points of a wave.

What are troughs?

The lowest points of a wave.

What is amplitude?

The maximum displacement from the rest position.

What is the SI unit for amplitude?

Metre (m).

What is wavelength (λ)?

The distance between two successive crests or two successive troughs.

What is the SI unit for wavelength?

Metre (m).

Does a loud sound have a larger or smaller amplitude than a soft sound?

Larger amplitude.

What are radio waves used for?

TV broadcasting and radar.

What are microwaves used for?

Global Positioning Systems (GPS).

What is a microwave oven used for?

Heating up food in a short time.

What other types of communication are microwaves used for?

Mobile phone and satellite communication.

What are infrared rays used for?

Remote control units and infrared thermometers.

What is visible light used for?

To help us see.

What process do plants use visible light for?

Photosynthesis.

What is visible light used for in technology?

High-speed data transmission through optical fibres.

Which electromagnetic waves have the longest wavelengths and lowest frequencies?

Radio waves.

Which electromagnetic waves have the shortest wavelengths and highest frequencies?

Gamma rays.

What are ultraviolet (UV) rays used for?

Forgery detectors.

How do ultraviolet rays affect our bodies?

Cause our bodies to become tanned and help our bodies produce vitamin D.

What is another use of ultraviolet rays?

To kill microbes and sterilise medical equipment.

How are X-rays used in medicine?

Radiation therapy to kill cancer cells.

What is a common medical application of X-rays?

To produce images of the body’s internal organs and bones.