ammeter, resist, and voltmeter in parallel with the resistor
- Vary the resistance of the variable resistor, which changes the p.d. of the circuit
- Measure current and p.d.
- Plot a V-I graph, and should be a straight line through the origin if Ohm's law is
followed
(9) Investigating resistivity - CORRECT ANSWER-- Measure diameter of wire with
micrometer at different points, find mean and then find area
- Vary length of wire
- Voltmeter in parallel and ammeter in series
- Calculate resistance R=V/I
- Plot graph of R/L, gradient is p/A
(10) Investigating Internal Resistance - CORRECT ANSWER-- Voltmeter in parallel
with the cell, ammeter and variable resistor in series
, - Vary resistance of variable resistor, measure current and terminal p.d.
- Take multiple readings and average
- Plot a V-I graph
- V = -rI + E
- Gradient of graph = negative internal resistance
(11) Using an oscilloscope to determine wave frequency - CORRECT ANSWER--
Connect a microphone to the oscilloscope, and this receives the sound waves
- Use the horizontal spaces (time) to find the time for the wave to complete one
oscillation
- 1/Period to find frequency
(11) Investigating polarisation of light - CORRECT ANSWER-- Use a vertical
polarising filter, which makes light become plane polarised
- Use a second vertical polarising filter, placed in the same plane, and slowly
rotate it
- Intensity of light should drop, and when it is 90 degrees to the vertical filter,
intensity falls to 0
(11) How to find refractive index - CORRECT ANSWER-- Draw a normal to the
material using set square or protractor
- Shine a ray from a ray box onto the material with monochromatic light
- Measure the angle of incidence of light, and the angle of refraction (both to the
normal)