Practical/Planning Flashcards
What is a safety precaution when using oil/water?
Mop up spillages of oil/water
What are 3 safety precautions when using a load?
- Cushion with sand in case load falls
- Keep feet away
- Keep distance from experiment
What is a safety precaution when using a ball?
Use a box with cushion to reduce bouncing/rolling
What is a safety precuation when using rotating/vibrating parts/pressure chamber?
Use a protective screen
What are 2 safety precautions when a hot body is used?
- Wear heat insulating gloves.
* Do not touch hot objects.
What are 2 safety precautions when a light source is used?
- Do not look directly at bright light source or wear dark glasses.
- Laser must be pointed away from experimenter.
What are 2 safety precautions when a source is used?
- Wear ear defenders
* Switch on sound source for short period of time.
What is a safety precaution when high voltage source is used?
Wear rubber gloves
What are 2 safety precautions when a normal/low voltage source is used?
- Switch off power supply when not in use to avoid overheating of wire.
- Do not touch coil because it is hot.
What are 3 safety precautions when radioactive items are used?
- The source is handled by a tong.
- The source is stored in a lead lined box when not in use.
- Avoid pointing source at people or /do not look directly at source.
How to measure time when time <10s and time >10s ?
> 10s:
Detection - Eye
Measuring device - Stopwatch
< 10s:
Detection - Light gates
Measuring device - Electronic timer
How to measure length/distance across different ranges?
> 1.0 m:
Measuring tape
Between 0.10 m – 1.0 m:
Metre rule
< 0.10 m:
Vernier callipers/micrometer screw gauge/travelling microscope
Travelling microscope is used when physical contact
with body is not recommended.
How to measure volume?
Immerse the body in a beaker of water and measure the volume of water displaced using measuring cylinder.
How to measure mass?
Electronic balance
How to measure angle?
Protractor or trigonometric methods
How to measure instantenous speed of an object?
detect using light gates indirect measurement speed v can be calculated using D/t D = fixed distance between light gates D kept small to get accurate instantenous speed t = time taken to travel distance D
Diagram: two light gates connected to a timer.
How to measure constant speed of a body? (slow speed)
detection: eye indirect measurement speed v can be calculated by D/t D = fixed distance using ruler t = time taken to travel D measured using stop watch
How to measure fast speed?
detect using light gates fire a rifle same as instanteous speed speed v =D/t D = fixed distance between light gates t = time taken
How to measure speed of water?
Create: tap supplying water to water tank
speed v can be calculated using v = V/A
V = flow rate of water (use flow rate meter)
A = cross sectional area of pipe
Diagram: Tap connected to basin vertically downwards connected to flow ratemeter and then to water out
How to measure wind speed?
Create: fan connected to variable power supply or has variable rotating speed
Direct measurement
Measure using wind speed detector
How to measure pressure of air/liquid?
Create: Pump connected to chamber
Pressure of air is recorded and measured using pressure gauge.
Diagram: Pump connected to chamber connected to pressure gauge
How to measure frequency of oscillating body?
f can be calcuated using f = 1/T
T = period of wave displayed on screen of CRO or time base x no. of division for one complete wave
Diagram: CRO connected to signal generator connected to oscillating body.
How to measure force?
Direct measurement using newton meter
Measurement: Using newton meter/spring balance
Diagram: Slotted mass hanging from cable connected to newton meter
How to measure angular speed of rotating body?
Connect body to shaft of electric motor
Detection device: Light gates
Angular speed calculated by 2π/T or 2πf
f measured by revolution counter or tachometer
How to measure temperature of solid body?
Place object in water bath and use a heating element
Measurement using thermometer
How to measure frequency of sound wave?
Detect using microphone connected to CRO
Create a loud speaker placed in front of a pipe
frequency calculated by 1/T
T = time base setting x no. of divisions for 1 complete wave
How to measure speed of sound in air
Create long tube fitted with tap & filled with water, tuning fork sounded above the top of the tube.
v = fλ
λ = 2L
L = difference in height of water level for 2 positions where loud sound is heard.
How to measure frequency of wire fixed between 2 ends?
Create an oscillator connected to a string secured by pulley and weight
Detect using eye
Measure using CRO
f = 1/T
T = time base setting x no of division for 1 wave on CRO.
How to measure frequency of light?
Detect by eye using the microscope
Measuring device: Spectroscope
f calculated by dsinθ = n(c/f)
Diagram: lamp and collimator connected to microscope and diffraction grating at the centre.
How to measure wavelength of microwave?
Create a microwave transmitter directed at a metal plate
Wavelength = 2 x L
L = distance moved by receiver for 2 consecutive positions where signal is at maximum.
Diagram: Transmitter connected to power suply directed to metal plate, with receiver connected to CRO in between
How to measure magnetic flux density?
Create circular coil connected to a power supply
Detection using hall probe
Measurement: Voltmeter
B = kV, k is a constant that is calculated by putting the hall probe into a known magnetic field.
State all additional details that should be considered.
- Mulitple readings of D.V using the same value of I.V to minimise random error
- Take preliminary readings in order to check range of I.V that causes significant change in D.V when readings are varied
- Use spirit level to ensure that items are aligned
- Repeat length measurements for different directions before taking average
- Contrasting colours with background used to ensure that it is easier to observe position
- Reduce external interference due to draughts by switching off fans
- Method to keep C.V constant: same apparatus used to ensure values are constant (same spring for same spring constant)
- Video camera used with playback feature to determine exact moment of motion
