Chapter 13: Electromagnetic Spectrum

Question 1

Define

Electromagnetic waves

Hint: in the name

Answer 1

Group of waves that consists of magnetic and electric field wave. Different wavelengths of electromag waves form the electromagnetic spectrum

Question 2

List

electromagnetic spectrum from highest freq to lowest

Low freq= long wavelength, high freq= short wavelength

Answer 2

Gamma ray(>10^18), Xray(10^16-18), Ultraviolet ray(10^14-16), Visible light(10^14), Infrared radiation(10^12-14), Microwaves(10^9-12), Radiowaves(<10^9)

Low freq= long wavelength, long freq= short wavelength

Grandma X usually likes Indian Muslim Rojak

Question 3

MCQ

Properties of electromagnetic waves

v = λ f!

1. Transverse or longitudinal, 2. Can Travel in vacuum?

Answer 3

Transverse, yes

Question 4

Speed of electromagnetic waves

What is the speed of waves dependent on

v = λ f!

Answer 4

3x10^8 m/s

dependent on medium

Question 5

List

Uses of Radiowaves

List

Answer 5

• Radio Astronomy
  * involves detecting and studying RW’s produced by planets & stars
• Radio Frequency Identification Tags (RFID tags)
  * contains small thin circuit. Reader device sends radio wave to tag, tag transmits back data to reader (commonly used to tag library books, etc.)
• Television & communication purposes
  * Longer wavelength radio waves are used as they can better travel ard obstacles like mountains

RW= radio waves

Question 6

List

Uses of microwaves

Answer 6

• Microwave Ovens
• Carries signals to and from satellites for satellite television, GPS, and phone communication
  * able to penetrate atmosphere, travel through haze, snow, light rain, cloud and smoke

Question 7

List

Uses of Infrared Radiation

Answer 7

• Intruder alarms
• Infrared cameras
• Remote controllers

Question 8

List

Visible Light

Answer 8

• allows us to see
• Used in optical fibres
• Photography

Question 9

List

UV radiation

Answer 9

• Sunbeds for artificial tanning
• Sterilisation of equipment and water(e.g. NEWater is disinfected using UV )
• Bank note authentication(authentic bank notes have pigments that glow under UV light)

Question 10

LIst

X-ray

Answer 10

• Used in chemotherapy
• Used for imaging for making medical diagnosis
• Used for imaging or security checks
• Industrial defect detection

Question 11

List

Gamma rays

Answer 11

• Targeted radiation therapy
• Sterilising food

Question 12

Types of Ionising radiation

2 types

Answer 12

1. Electromagnetic radiation 2. Nuclear radiation

Question 13

Define

Ionising radiation

Answer 13

higher frequency forms of radiation that has sufficient energy to cause ionisation of medium through which it pass

ionisation- knock out an electronm from a particular atom or molecule

able to penetrate deep into the body making them extremely harmful

Question 14

name

effect of ionising radiation on living cells

Answer 14

1. death of living cells
2. mutation of living cells, leading to organ failure and diseases
3. heating up of living cells

Question 15

name

types of electromag waves that are ionising radiation

Answer 15

1. Gamma rays
2. X-rays
3. Ultraviolet rays