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:
3 years
Explanation:
Find the circumference of each orbit in AU.
2xπx1=6.283185307
2xπx3=18.84955592
Divide them.
18.84955592/6.283185307=3
3 years
A. 1.35 is the number in between 1.2 and 1.5.
In this question, one has to carefully understand that the total
number of hours in the day can never be more that 24 hours. based on
this important fact the answer to the question can be very easily
deduced. The only requirement is calculating perfectly.
Number of hours in a day = 24 hours
Percentage of hours of sleep in a day = 33%
Amount of sleep in the day = (33/100) * 24
= 7.92 hours
So 33% of sleep in a day is equal to 7.92 hours. I hope this answer has helped you. In future you can keep the procedure in mind for solving such problems.
