Answer:
D
A machine can help decrease the input force and increase the output force.
In a double-slit interference experiment, the distance y of the maximum of order m from the center of the observed interference pattern on the screen is

where D=5.00 m is the distance of the screen from the slits, and

is the distance between the two slits.
The fringes on the screen are 6.5 cm=0.065 m apart from each other, this means that the first maximum (m=1) is located at y=0.065 m from the center of the pattern.
Therefore, from the previous formula we can find the wavelength of the light:

And from the relationship between frequency and wavelength,

, we can find the frequency of the light:
Answer:
Distance between centre of Earth and centre of Moon is 3.85 x 10⁸ m
Explanation:
The attractive force experienced by two mass objects is known as Gravitational force.
The gravitational force is determine by the relation:
....(1)
According to the problem,
Mass of Moon, m₁ = 7.35 x 10²² kg
Mass of Earth, m₂ = 5.97 x 10²⁴ kg
Gravitational force experienced by them, F = 1.98 x 10²⁰ N
Universal gravitational constant, G = 6.67 x 10⁻¹¹ Nm²kg⁻²
Substitute these values in equation (1).



d = 3.85 x 10⁸ m
Potential energy decreases and kinetic energy increases.
Potential energy is related to the height, since the wagon is going downhill, height decreases and potential energy decreases.
Kinetic energy is related to the speed, since the wagon is speeding up, kinetic energy increases.