The Electromagnetic Spectrum

Question 1

What is the electromagnetic spectrum?

Answer 1

The electromagnetic spectrum is a range of waves that are not mechanical, meaning they do not need a medium to travel in. They are all transverse waves and travel at the same speed, but each type has different frequencies and wavelengths.

Question 2

Which type of electromagnetic wave has the shortest wavelength and highest frequency?

Answer 2

Gamma rays have the shortest wavelength and the highest frequency.

Question 3

Which type of electromagnetic wave has the longest wavelength and lowest frequency?

Answer 3

Radio waves have the longest wavelength and the lowest frequency.

Question 4

What are some uses of gamma rays?

Answer 4

Gamma rays are used in cancer treatment and sterilizing medical equipment due to their high energy.

Question 5

What is the range of visible light in the electromagnetic spectrum?

Answer 5

Visible light ranges from violet to red in the electromagnetic spectrum.

Question 6

How do microwaves differ from infrared waves in terms of wavelength and frequency?

Answer 6

Microwaves have longer wavelengths and lower frequencies compared to infrared waves.

Question 7

What is a practical application of ultrasound mentioned in the image?

Answer 7

Ultrasound is used in medicine to create images of the inside of the body, such as viewing unborn babies.

Question 8

What are gamma rays and what is their speed in a vacuum?

Answer 8

Gamma rays are waves with the smallest wavelength and highest frequency. Their speed in a vacuum (or air) is 300,000,000 m/s (3x10^8 m/s).

Question 9

What are some uses of gamma rays in medicine?

Answer 9

Gamma rays are used to kill cancer cells in patients and to sterilize medical equipment by killing bacteria.

Question 10

Why are X-rays used in airports and industry?

Answer 10

X-rays are used in airports to scan luggage and in industry to inspect welding because of their ability to penetrate materials and reveal hidden structures.

Question 11

What are the effects of ultraviolet (UV) rays on human skin?

Answer 11

UV rays can cause our skin to get red or sunburnt because they have enough energy to affect the DNA structure of our cells.
Overexposure to UV rays can lead to severe cellular damage and increase the risk of skin cancer.

Question 12

What is visible light and what makes it unique in the electromagnetic spectrum?

Answer 12

Visible light is the only part of the electromagnetic spectrum that can be seen by the human eye. It consists of seven colors (violet, indigo, blue, green, yellow, orange, and red), each with its own wavelength.

Question 13

How do infra-red (IR) rays interact with objects?

Answer 13

Infra-red rays have a longer wavelength and lower frequency than visible light. When absorbed by objects, IR rays cause them to heat up. This property is used in various applications, such as heat detection and remote controls.

Question 14

How are UV rays used in detecting counterfeit banknotes?.

Answer 14

UV rays are used to detect counterfeit banknotes because certain features on genuine banknotes fluoresce under UV light, making it easier to identify fakes.

Question 15

What are some practical applications of infra-red rays?

Answer 15

Infra-red rays are used in fire-fighting to search for unconscious people in smoke-filled buildings, in remote controllers for TVs and video players, and in automatic doors and lights that activate when IR sensors detect movement.

Question 16

Why is it important to protect oneself from overexposure to UV rays?

Answer 16

Overexposure to UV rays can cause severe cellular damage, increase the risk of skin cancer, and lead to other health issues such as premature aging of the skin.

Question 17

What are the properties of microwaves compared to infrared (IR) waves?

Answer 17

Microwaves have a longer wavelength and a lower frequency than infrared (IR) waves.

Question 18

How do microwaves cause water to heat up?

Answer 18

Microwaves of a certain frequency cause water molecules to vibrate, which generates heat. This is the principle used in microwave ovens for cooking food.

Question 19

What are some common uses of microwaves?

Answer 19

Microwaves are used for cooking in microwave ovens, mobile phone communication, satellite communication, and radar.

Question 20

Describe the energy conversions that occur when speaking on a mobile phone.

Answer 20

When speaking on a mobile phone, sound energy is converted to electrical energy, then to microwave energy. When hearing, microwave energy is converted back to electrical energy and then to sound energy.

Question 21

How are microwaves used in radar technology?

Answer 21

Microwaves are used in radar technology to detect objects and measure their distance and speed by emitting microwave signals and analyzing the reflected waves.

Question 22

Why are microwaves suitable for satellite communication?

Answer 22

Microwaves are suitable for satellite communication because they can travel long distances through the atmosphere without being significantly absorbed or scattered.