Answer
D) burning a candle
Explanation
When burning a candle no new substance is form.
We have both physical and chemical change occuring.
Physical part: Melting of the solid wax and evaporation of the liquid forms the physical change.
Chemical part: burning of the wax vapour forms the chemical change.
Answer:
3 photons
Explanation:
The energy of a photon E can be calculated using this formula:
Where 
corresponds to Plank constant (6.626070x10^-34Js), 
is the speed of light in the vacuum (299792458m/s) and 
is the wavelength of the photon(in this case 800nm).
Tranform the units
The band Gap is 4eV, divide the band gap between the energy of the photon:
Rounding to the next integrer: 3.
Three photons are the minimum to equal or exceed the band gap.
Answer:
Distance
Explanation:
distance is in vertical axis,or y-axis and time is on the horizontal axis,or x-axis.
To the Earth in less than ten minutes.
