Answer:
The speed of this light and wavelength in a liquid are 
and 442 nm.
Explanation:
Given that,
Wavelength = 650 nm
Index refraction = 1.47
(a). We need to calculate the speed
Using formula of speed
Where, n = refraction index
c = speed of light in vacuum
v = speed of light in medium
Put the value into the formula
(b). We need to calculate the wavelength
Using formula of wavelength
Where, 
= wavelength in vacuum
= wavelength in medium
Put the value into the formula
Hence, The speed of this light and wavelength in a liquid are and 442 nm.
Can i have more information?
Answer:
At an angle of 
Explanation:
Assume the river flows from East to West so for the swimmer to cross across it, assume he crosses it from West to East.
The resultant speed will be given by
Answer:
v = -v₀ / 2
Explanation:
For this exercise let's use kinematics relations.
Let's use the initial conditions to find the acceleration of the electron
v² = v₀² - 2a y
when the initial velocity is vo it reaches just the negative plate so v = 0
a = v₀² / 2y
now they tell us that the initial velocity is half
v’² = v₀’² - 2 a y’
v₀ ’= v₀ / 2
at the point where turn v = 0
0 = v₀² /4 - 2 a y '
v₀² /4 = 2 (v₀² / 2y) y’
y = 4 y'
y ’= y / 4
We can see that when the velocity is half, advance only ¼ of the distance between the plates, now let's calculate the velocity if it leaves this position with zero velocity.
v² = v₀² -2a y’
v² = 0 - 2 (v₀² / 2y) y / 4
v² = -v₀² / 4
v = -v₀ / 2
We can see that as the system has no friction, the arrival speed is the same as the exit speed, but with the opposite direction.
Work=f.d
Work=100*50 = 500
Power = work/time = 500/4
=125 watt
