Answer:
0.714 m
Explanation:
From the question,
v = λf......................... Equation 1
Where v = velocity of visible light, f = frequency of visible light, λ = wave length of visible light.
make λ the subject of the equation
λ = v/f.................. Equation 2
Given: f = 4.2×10⁸ Hz
Note: Light is an electromagnetic wave, and all electromagnetic waves travels with the same speed (3×10⁸ m/s)
Constant: v = 3×10⁸ m/s
Substitute these values into equation 2
λ = 3×10⁸/4.2×10⁸
λ = 0.714 m
Answer:
5000 m equivalent to 5 Km
Explanation:
Average velocity =
so, Displacement =Average velocity × time
We should convert Km/h to m/s so Km/h ⇒ 
m/s, also convert time to second so, 20min ⇒(20* 60)seconds
Displacement = (15 ×) × (20×60) =5000m OR 5Km
Answer: Eclipse
Explanation: A lunar eclipse occurs when the full moon moves through the shadow of the Earth. This can only happen when the Earth is between the Moon and the Sun and all three are lined up in the same plane, called the ecliptic. The ecliptic is the plane of Earth's orbit around the Sun.
