Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

LC Physics > Exam qs > Flashcards

Exam qs Flashcards

1
Q

why a compass points North

A

north end of a magnet attracted to south magnetic pole and vice versa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Refractive index (of a medium)

A

ratio of the sine of angle of incidence to the sine of the angle of refraction when light travels from a vacuum into that medium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

critical angle

A

when light travels from a denser to a rarer medium, the angle of incidence whose corresponding angle of refraction is 90° is called the critical angle for those two media

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

application of internal reflection

A

optical fibres

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

how energy from the sun is transferred to Earth

A

transferred from sun to earth via electromagnetic radiation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

weight

A

force with which a body is attracted to Earth or another celestial body

w = mg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

directions of electric fields

A

radially inwards or radially outwards

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Total R of 3 resistors in parallel proof (derivation)

A

on sheet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

lens for myopia

A

diverging lens

diverges beam of light to fall on retina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

lens for hyperopia

A

converging lens

converges beam of light to fall on retina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

resistance

A

R of a conductor is the ratio of the p.d. across it to the current flowing through it

R = V/I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

angular V and linear V

A

derivation needed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

relationship between v, u and object + image heights

A

U/V = Hₒ/Hᵢ

or

U/v Hᵤ/Hᵥ

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

lens strength and eye lengths and names of conditions

A

myopia = lens too strong = eye too long

hyperopia = lens too weak = eye too short

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

angular velocity

A

rate of change of angle with respect to time

W = Θ/t + notation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

why the cornea does not act as a lens underwater

A

light not retracted at cornea

water and cornea have same n value

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

max power of the eye underwater

A

26 m⁻¹ (*for specific qs)
in order to get:
max power of eye underwater = max power of eye - power of cornea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

why objects appear blurred underwater

A

internal lens not powerful enough to focus light on retina

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

how goggles allow us to see underwater

A

light refracted upon passing from air to cornea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

sound intensity + sound intensity level

A

doubling sound intensity increases SI level by 3 dB

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

spectrometer diagram

A

on sheet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

how to get a line spectrum

A

use gaseous lamp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

how to get a continuous spectrum

A

use white light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

to produce two coherent sources of light

A

diagram on sheet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

why pipe open at one end produces half no. of harmonics as pipe open at both ends

A

textbook

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

why satellites will be above a diff point in earth’s surface after a 24 hour period

A

they are not a geostationary orbit, they have diff period to that of the Earth’s rotation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Newton

A

force that gives a mass of 1 kg an acceleration of 1 m/s²

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

deriving a = -w²s

A

on sheet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

sound intensity

A

rate at which sound energy is passing through unit area at right angles to the direction in which the sound is travelling at that point

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

conduction

A

transfers heat via direct molecular collision / transfer of heat energy by direct contact

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

convection

A

energy transition occurs within the fluid / heat transfers by real movement of matter in fluids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

radiation

A

movement of heat in waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

transmission of light through an optical fibre

A
  • light enters fibre + strikes inside of fibre at angle greater than critical angle
  • total internal reflection occurs
  • ray is reflected to opposite side + total internal reflection occurs again
  • process continues + light travels through fibre

-diagram needed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

1 sec in millisec

A

1 second = 1000 milliseconds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

how a rotating object can be in equilibrium

A

a rotating body can be in equilibrium if the body is not rotating with angular acceleration.
This means the body is rotating at a constant rate and is moving at constant velocity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

derive relationship between period of a satellite, radius of its orbit, and mass of earth

A

on sheet

37
Q

advantage of electric cars

A

-fewer carbon emissions

38
Q

disadvantage of electric cars

A
  • short range

- expensive batteries

39
Q

seismometer - what type of motion does the fram have when it moves relative to the mass?

A

simple harmonic motion

40
Q

seismometer - forces on it when at rest

A
  • weight acting downwards

- tension acting upwards

41
Q

…explain why an emf is generated in the coil

A

magnetic field passing through the coil is changing

42
Q

assumptions in making calculations of someone falling

A
  • no atmospheric resistance
  • g constant
  • u is taken as zero
43
Q

spacecraft is flying from earth to moon. and after a while its engines are turned off. Why does it continue on its journey even after engines are turned off?

A

according to Newton’s first law of motion: a body remains at rest or moving with uniform velocity in a straight line unless an unbalanced force acts on it

44
Q

describe the variation in weight of astronauts as they travel to the moon

A

weight decreases to zero as they move away from earth and gains a lesser than normal weight as they approach moon

45
Q

at what height above the earth’s surface will the astronaut experience weightlessness?

A

gravitational pull of earth = gravitational pull of moon

use formula for gravitational force

46
Q

why is there no atmosphere on the moon?

A

gravitational force too weak to sustain atmosphere

47
Q

how does resonance occur in an acoustic guitar

A

energy transferred from strings to hollow body

both vibrate at same freq

48
Q

What primary colours of light are absorbed when white light shines on a red book and what are reflected?

A

absorbed: green and blue
reflected: red

49
Q

what colour would red book appear to if it was illuminated with green light and then with red light

A

1: black
2: red

50
Q

application of stress polarisation

A

checking for defects

51
Q

define wavelength

A

distance between two crests/troughs

52
Q

where in they eye are sensors that respond to photons located?

A

retina

53
Q

state differences between electromagnetic radiation emitted from a laser and emitted from a vapour lamp

A
  • laser has one freq/wavelength only
  • laser light is more powerful
  • laser light is coherent
  • laser light is collimated
54
Q

nearsightedness

A

myopia

55
Q

farsightedness

A

hyperopia

56
Q

extra diagrams

A

go thru papers and on sheet

57
Q

experiment to find resultant of 2 vectors

A

-diagram

  • set up as shown, spring balances graduated in Newtons)
  • adjust size + direction of three forces until knot in thread remains at rest
  • if we want resultant of two forces, F1 and F2, its magnitude is the reading on the third balance (F3). Direction is opposite direction to F3
58
Q

why occupants of satellite experience weightlessness

A

they are in freefall

59
Q

period of geostationary satellite

A

1 day (24 hours)

60
Q

why fiber glass is coated with glass of low ref index

A

so total internal reflection occurs and no light escapes

61
Q

white light thru prism vs diff grating

A

prism: one spectrum, red light deviated least
grating: multiple spectra observed, red light deviated most

62
Q

detecing UV rays

A

makes object glow

63
Q

detecting Infrared rays

A

thermometer/temp sensor

64
Q

establishing calibration curve for thermocouple

A
  • one junction of constant temp, other in water w thermom
  • heat water in steps of 10 C. Note emf + temp each time
  • plot graph of emf vs temp
65
Q

coherent source

A

two waves are coherent if: have constant phase change, same freq, same waveform

66
Q

conditions for total destructive interference

A

same amplitude

out of phase when crest meets trough

67
Q

resonance experiment

A

use resonance tube or sonometer

68
Q

why note sounds diff in diff instruments

A

diff instruments emit diff overtones

69
Q

doppler effect experiment

A

buzzer attached to string
swing source attached to string
note freq change when source passes observer

70
Q

properties of radio waves

A

travel at speed of light

can be polarised

71
Q

what happens when radio wave freq are absorbed into body

A

converted into heat

carried away by body

72
Q

safety precautions when using phones

A

keep phone at distance
use loudspeaker
brief calls only

73
Q

cancer-inducing electromagnetic wave

A

UV rays

causes ionisation of body cells

74
Q

white light thru grating: how grating produces a spectrum

A

diff colours have diff wavelengths, constructive interference occurs

75
Q

why spectrum not formed at central image

A

at central image, theta/angle = 0

76
Q

How is energy transferred from the sun to the earth?

A

by means of) radiation / photons / electromagnetic waves

77
Q

A pendulum moves with simple harmonic motion. Give another example of a body that moves with SHM.

A

a mass oscillating on a spring

78
Q

when asked for the displacement/acceleration/centripetal acceleration in a question / for vectors

A

dont forget to write direction

79
Q

gravity formula what d stands for

A

the radius (the height + radius of earth)

80
Q

Why does the value of g, acceleration due to gravity, vary at different locations on the surface on the earth?

A

locations are at different distances from the earth’s centre / earth is not perfectly spherical / etc.

81
Q

Why is a convex mirror used, instead of a plane mirror, as a door mirror on a car?

A

wider / greater field of view / any valid answer

82
Q

What causes the Doppler effect?

A

(relative) motion between source (of waves) and observer

83
Q

processes by which a hot drink cools

A

evaporation
conduction
radiation
convection

84
Q

how energy lost in a hot drink can be reduced in a disposable cup

A

lid
insulation (eg. cardboard holder)
bright inside surface (for radiation)

85
Q

At night, when the lamp is switched on, a disc of light is seen at the surface of the swimming pool. Explain why the area of water surrounding the disc of light appears dark.

A

(no light emerges from pool due to) total internal reflection / appropriate diagram

86
Q

Explain why snow is slow to melt as the air temperature rises above 0 °C. (7)

A

Because water has a high specific latent heat of fusion and a lot of energy needs to be taken in by ice in order to change state.

87
Q

spring constant unit

A

N m^-1

N/m

88
Q

The red line emitted by a hydrogen discharge tube in the laboratory has a wavelength of 656 nm. The same red line in the hydrogen spectrum of a moving star has a wavelength of 720 nm. Is the star approaching the earth? Justify your answer

A

no

wavelength has increased // frequency has decreased

89
Q

what is friction

A

a force that opposes motion / tries to prevent one surface sliding over another

LC Physics (25 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions