Answer:

Explanation:
We need to find the energy for an electron to jump from n = 1 to n = 4.
The energy in transition from 1 state to another is given by :

The difference in energy for n = 1 to n = 4 is:

So, the required energy is equal to
.
Answer:
The center of mass of the Earth-Moon system is 4.673 kilometers away from center of Earth.
Explanation:
Let suppose that planet and satellite can be treated as particles. The masses of Earth and Moon (
,
) are
and
, respectively. The distance between centers is 384,403 kilometers. The location of the center of mass can be found by using weighted averages:

If
and
, then:


The center of mass of the Earth-Moon system is 4.673 kilometers away from center of Earth.
The distance between two successive troughs or crests is known as the wavelength. The wavelength of the light will be 1000 nm.
How do you define wavelength?
The distance between two successive troughs or crests is known as the wavelength. The peak of the wave is the highest point, while the trough is the lowest.
The wavelength is also defined as the distance between two locations in a wave that have the same oscillation phase.
Diffraction angle= 30⁰
Diffraction grating per mm= 250
wavelength = ?
Mathematically the equation of bright band is given by


m

Hence the wavelength of the light will be 1000 nm.
To learn more about the wavelength refer to the link;
brainly.com/question/7143261
Answer:
Relative to the ground, the velocity of the aircraft is 240 km/hr
Explanation:
Relative velocity is different from normal velocity;
When 2 objects are moving in opposite directions towards each other, they will appear to be faster than they actually are;
This is known as the relative velocity;
The information tells us we have the aircraft moving 320 km/hr northwards relative to the wind;
The wind is in the opposite direction at 80 km/hr;
R = relative velocity of the aircraft
v = actual velocity of the aircraft
w = velocity of the wind
R = v + w
Note: if the wind was moving in the same direction, the formula would be R = v - w
320 = v + 80
v = 320 - 80
v = 240
The velocity relative to the ground is simply the actual velocity as the ground doesn't move;
So, relative to the ground, the velocity of the aircraft is simply 240 km/hr
An object in motion stays in motion while an object at rest stays at rest.