Answer:
Systematic errors.
Explanation:
The density of the aluminium was calculated by a human and this is not natural but can be due to errors in the calibration of the scale for measuring the weight or taking readings from the measuring cylinder.
Random errors are natural errors. Random errors in experimental measurements are caused by unknown and unpredictable changes in the experiment. Systematic errors are due to imprecision or problems with instruments.
Choice C.
That's when convection stops.
Light waves are reflected from front and back surfaces of the thin films and constructive interference between the two reflected waves occurs in different places for different wavelengths. Light shining on the upper surface of the thin film with thickness t is partly reflected at the upper surface (path abc). Light transmitted from the upper surface is partly reflected at the lower surface (path abdef). The two reflected waves come together at point P on the retina of the eye. Depending on the phase relationship, they may interfere constructively or destructively. Different colors have different wavelengths, so the interference may be constructive for some colors and destructive for others.
In a transverse wave:
- Oscillations are perpendicular to the direction of energy travelling
- Frequency is the amount of complete waves passing a certain point in one second (measured in hertz, Hz)
- Wavelength is the distance from any point on one wave to the same point on the following wave
- The amplitude is the maximum displacement of the particles from their average position (and be measured from the horizontal mid-point of the wave to either the peak or trough)
There isn't always a defined relationship between these features. However, frequency × wavelength = velocity of the wave.