Targeted Flashcards
What is the range of human hearing?
20 Hz - 20,000 Hz/20kHz
Why do U.V rays have many more risks than Infrared radiation?
U.V Rays are of a higher frequency than Infrared radiation, and therefore do not have to be emmited from a such a high intensity source to cause damage.
List 3 advantages of using gamma rays to treat tumors
- it accurately targets the tumor
- no anaesthetic is used in the treatment
- it is an outpatient procedure
- the procedure does not affect the patient’s entire body
- no surgery / invasive operation is used
(any of the above)
When linear magnification of a lense is negative or positive, what effect does this have on the image produced?
When negative, the image is virtual. When positive, the image is real.
Why did Scientist’s attitudes towards space change when Jupiter’s moons were discovered?
They realised that space wasn’t geocentric. Other celestial bodies orbit around other planets. Not every planet orbits around earth.
Why might a ray of light not change direction when initally shone into glass?
If the light is shone along the normal, it will not change direction when it enters the medium.
What is the role of mirrors and the eyepiece lense in a telescope?
- light rays initally enter the curved mirror
- they are reflected onto the plane mirror, which inverts the image
- the rays converge before it reaches the eyepiece lense
- it is then reflected into the eyepiece lense, which magnifies the image
What is the approximate wavelength of visible light?
500 nm / 0.5 µm
How does the earth heat up?
(Relate this back to power/energy in and out)
When the total power absorbed by the earth is more than the power emmited to space by it, the earth’s energy store begins to rise. The energy store will continue to increace untill the total power out and the power in are equal.
What is work done?
(and the equation)
The amount of force needed to move an object a certain distance.
Work Done = force x distance
