Answer:
2.7 J
Explanation:
The energy of one photon is given by
where
h is the Planck constant
f is the frequency
For the photons in this problem,
So the energy of one photon is
The number of photons contained in 1.0 mol is
(Avogadro number)
So the total energy of 
photons contained in 1.0 mol is
Answer:
The acceleration is 
and the distance covered is 97.17 m.
Explanation:
Given that,
Initial speed of an automobile, u = 60 km/hr = 16.67 m/s
Final speed of an automobile, v = 80 km/hr = 22.2 m/s
Time, t = 5 s
We need to find the acceleration of the car and the distance traveled in this 5 sec interval. Let a is the acceleration. Using the definition of acceleration as :
Let d is the distance covered. Using the third equation of motion to find it as follows :
So, the acceleration is and the distance covered is 97.17 m.
Charge on can A is positive.
Charge on can C is negative.
Punctuation and capitalization are very useful things to pay attention to and this question would be a lot easier to understand if you had actually used both capitalization and punctuation. If I'm understanding the question, you have 3 metal can that are insulated from the environment and initially touching each other in a straight line. Then a negatively charged balloon is brought near, but not touching one of the cans in that line of cans. While the balloon is near, the middle can is removed. Then you want to know the charge on the can that was nearest the balloon and the charge on the can that was furthermost from the balloon.
As the balloon is brought near to can a, the negative charge on the balloon repels some of the electrons from can a (like charges repel). Some of those electrons will flow to can b and in turn flow to can c. Basically you'll have a charge gradient that's most positive on that part of the can that's closest to the balloon, and most negative on the part of the cans that's furthest from the balloon. You then remove can B which causes cans A and C to be electrically isolated from each other and prevents the flow of elections to equalize the charges on cans A and C when the balloon is removed. So you're left with a deficiency of electrons on can A, so can A will have a positive overall charge, and an excess of electrons on can C, so can C will have a negative overall charge.
Answer:
The critical angle for a diamond in air is 24 degrees, while the critical angle for glass is 41 degrees.
Explanation:
Rays exiting the material at an angle less than the critical angle will be refracted, and rays incident on the interface at greater than the critical angle will be totally reflected back inside the material.
