Physics things you need to know

Question 1

x rays properties

Answer 1

• the affect a photographic film in the same way as light
• they are absorbed by metal and bone
• they are transmitted by soft tissue
• their wavelength is of the same order of magnitude as the diameter of an atom

Question 2

what is refraction

Answer 2

refraction is the change of light as it passes from one medium to another

Question 3

how does a lens for and image

Answer 3

a lens forms an image by refracting light

Question 4

how do you correct short sight

Answer 4

DIVERGING LENS
negative power,
divereges light rays before they go into the eye so they form on the retina

Question 5

how do you correct long sight

Answer 5

CONVERGING LENS
positive power
converges light rays before they enter the eye so they form on the retina

Question 6

what is the cornea

Answer 6

the cornea is the transparent window with a convex shape it has a high refractive index, does most of the eyes focusing

Question 7

what is the lens

Answer 7

the lens changes shape to focus light from varying differences

Question 8

the focal length

Answer 8

for a given force length the greater the refractive index the flatter the lens

Question 9

how does a hydraulic act as a force multiplier

Answer 9

the use of different cross-sectional areas on the effort and load side of a hydraulic system enables the system to be used as a force multiplier

Question 10

what is the motor effect

Answer 10

the motor effect is the

Question 11

how do you increase the size of the force

Answer 11

increase the strength of the magnetic field

increase the size of the current

Question 12

how do you induce pd

Answer 12

if a magnet is moved into a coil of wire a potential difference is induced across the ends of the coil

Question 13

step up transformer

Answer 13

the pd across the secondary coil is greater than the pd across the primary coil

Question 14

step down transformer

Answer 14

the pd across the secondary coil is less than the pd across the primary coil

Question 15

whats the frequency of a switch mode transformer

Answer 15

50KHZ - 200 KHZ

Question 16

if the angle of incidence is less than

Answer 16

the critical angle then most light passes out but a little is internally reflected

Question 17

if the angle of incidence is equal to

Answer 17

the critical angle most is internally reflected and a little light comes out

Question 18

if the angle of incidence greater than

Answer 18

the critical angle then all is internally reflected