Physics - WAVES (P6)

General Wave Properties -

What is a wave?

A disturbance that transfers energy from one place to another w/out transferring matter.

General Wave Properties -

What is the difference between a transverse + longitudinal wave?

Transverse: oscillations are perpendicular to the direction of energy transfer

Longitudinal: oscillations are parallel to the direction of energy transfer

General Wave Properties -

Give two examples of transverse waves.

Light waves, water waves.

General Wave Properties -

Give an example of a longitudinal wave.

Sound wave.

General Wave Properties -

What is the amplitude of a wave?

The maximum displacement from the rest position.

General Wave Properties -

What is the wavelength?

The distance between two corresponding points on adjacent waves.

General Wave Properties -

What is the frequency of a wave?

The number of waves passing a point per second, measured in hertz (Hz).

General Wave Properties -

What is the wave speed equation?

wave speed = frequency x wavelength

Required Practical: Measuring Waves -

In the ripple tank experiment, what do you measure to find wave speed?

Measure wavelength (using a strobe + ruler) + frequency (using timer), then use wave speed = frequency x wavelength.

Required Practical: Measuring Waves -

In the spring (slinky) experiment, how is wave speed measured?

Measure frequency + wavelength of transverse / longitudinal waves on a stretched spring.

Reflection, Refraction, + Transmission -

What is reflection?

The bouncing back of a wave at a surface.

Reflection, Refraction, + Transmission -

What is the law of reflection?

Angle of incidence = angle of reflection.

Reflection, Refraction, + Transmission -

What is refraction?

The change in direction of a wave when it passes from one medium to another.

Reflection, Refraction, + Transmission -

Why do waves refract?

Because their speed changes when moving between different materials.

Reflection, Refraction, + Transmission -

What happens to wave speed + wavelength when a wave enters a denser medium?

Speed decreases, wavelength decreases.

Reflection, Refraction, + Transmission -

What stays the same during refraction?

Frequency.

The Electromagnetic Spectrum -

List the electromagnetic waves in order of increasing frequency.

Radio, microwave, infrared, visible, ultraviolet, X-rays, gamma rays.

The Electromagnetic Spectrum -

What is the speed of all EM waves in a vacuum?

3.0 × 10(to the power of 8) m/s

The Electromagnetic Spectrum -

Which EM waves are ionising?

Ultraviolet, X-rays, gamma rays.

The Electromagnetic Spectrum -

Name two uses of radio waves.

TV + radio broadcasting, communication.

The Electromagnetic Spectrum -

Name one use of microwaves.

Satellite communication, cooking.

The Electromagnetic Spectrum -

Name one use of infrared radiation.

Remote controls, thermal imaging, heating.

The Electromagnetic Spectrum -

Name one use of ultraviolet radiation.

Fluorescent lamps, security marking.

The Electromagnetic Spectrum -

Name one use of X-rays.

Medical imaging (to see bones).

The Electromagnetic Spectrum -

Name one use of gamma rays.

Sterilising equipment, cancer treatment.

The Electromagnetic Spectrum -

What are the health risks of ultraviolet radiation?

Skin aging, sunburn, increased risk of skin cancer.

The Electromagnetic Spectrum -

What are the health risks of X-rays + gamma rays?

Can cause mutations in cells, increasing cancer risk.

Visible Light & Lenses -

What are the colours of the visible spectrum (in order)?

Red, orange, yellow, green, blue, indigo, violet (ROYGBIV).

Visible Light & Lenses -

What is a convex lens?

A lens that brings light rays together (converges them).

Visible Light & Lenses -

What is a concave lens?

A lens that spreads light rays apart (diverges them).

Absorption, Transmission, + Reflection -

What determines the colour of an opaque object?

The wavelengths of visible light it reflects.

Absorption, Transmission, + Reflection -

What happens to light in a black object?

It is absorbed.

Absorption, Transmission, + Reflection -

What do transparent objects do to light?

Transmit it.

Sound Waves + Ultrasound -

Ultrasound + seismic waves may be omitted / simplified.