The answer is 45 degrees.
According to the Kinematics of projectile motion, if the purpose is to maximize range, optimum angle of landing is always 45 degrees.If the purpose is to maximize range & projection height is zero, the optimum angle of projection (and landing) is 45 degrees.
Answer
When an electron makes transition from a state of higher energy to a state of lower energy it does so by emitting energy in form of radiation in the visible spectrum of light.
Since the basic postulates of the atomic theory is that the energy that the electron possess in it's orbit's takes only discrete values and cannot take any random value thus when an electron makes a transition from a state of higher energy to state of lower energy it will emit radiation with energy equal to difference between the energy levels of the 2 orbit's thus we only observe discrete lines.
Mathematically when an electron makes a transition between states the wavelength of light it releases is given by

where
is Rydberg constant
is upper energy level
is lower energy level
thus we can see that only discrete wavelength's are released and not continuous wavelength's of light.
<h3><u>Answer and explanation;</u></h3>
Reflection;
- Bounces back from an opaque material
- Bounces back from the boundary of two mediums
- Seen in mirrors
Refraction;
- Passes through a prism
- Moves from one medium to another
- Seen in lenses
Reflection refers to the bouncing of waves such as light waves. It involves a change in direction of waves when they bounce off a barrier.
Refraction is the bending of waves when they move from one medium to another. It involves a change in the direction of waves as they pass from one medium to another.
Answer:
•→ The motion of a particle or body in S.H.M acts towards a fixed point.
•→ Acceleration of the body under S.H.M is proportional to its displacement.
•→ This motion is periodic.
•→ Mechanical energy is conserved in S.H.M
Explanation:
S.H.M is Simple Harmonic Motion

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