Fig. 17.1 shows the electromagnetic spectrum arranged in order of increasing wavelength. Type Use Danger Gamma rays ........ ........ Microwaves ........ .....
Question 1 Report
Fig. 17.1 shows the electromagnetic spectrum arranged in order of increasing wavelength.
| Type | Use | Danger |
|---|---|---|
| Gamma rays | ........ | ........ |
| Microwaves | ........ | ........ |
| Infrared | ........ | ........ |
(a) Complete the table with one use and one danger for each type. [6]
(b) State the speed of all electromagnetic waves in a vacuum. [1]
(c) State which end of the spectrum has the highest energy. [1]
Answer Details
(a) Complete the table with one use and one danger for each type [6]
| Type | Use | Danger |
|---|---|---|
| Gamma rays | Sterilising medical equipment / treating cancer (radiotherapy) [1] | Can cause cancer / cell damage / mutations [1] |
| Microwaves | Cooking food / mobile phone communication / satellite communication [1] | Internal heating of body tissue [1] |
| Infrared | Remote controls / thermal imaging / heating [1] | Skin burns / tissue damage [1] |
Each type of electromagnetic radiation has properties that make it useful for specific applications but also potentially hazardous. Gamma rays carry the most energy per photon, making them effective at destroying bacteria (sterilisation) or cancer cells (radiotherapy), but that same energy can ionise healthy cells and damage DNA. Microwaves penetrate into food and are absorbed by water molecules, making them ideal for cooking, but they can similarly heat body tissues internally. Infrared radiation is emitted by all warm objects and can be detected for thermal imaging, but concentrated infrared causes burns.
(b) Speed of all electromagnetic waves in a vacuum [1]
3 × 108 m/s [1]
This is one of the fundamental constants of physics. All electromagnetic waves, regardless of type, travel at this same speed in a vacuum.
(c) Which end of the spectrum has the highest energy [1]
The gamma-ray end (shortest wavelength, highest frequency). [1]
Energy is proportional to frequency (\(E = hf\)). Since gamma rays have the highest frequency, they carry the most energy per photon. This is why they are the most penetrating and most dangerous type of electromagnetic radiation.
Download The App On Google Playstore
Everything you need to excel in your exams
