Answer : Time taken for the light to reach earth is 
Explanation :
Given that,
Speed of Ultraviolet light, 
Distance covered by the light, 
We have to find the time taken (t) by the light to reach on the surface of earth.
t = 133333333.333 seconds
or
Hence, this is the required solution.
Resistance = ρ * (L/A) and Rf = Ri * ([1 + α * (Tf – Ti)]
ρ = Resistivity L = length in meters A = cross sectional area in m^2 α = temperature coefficient of resistivity
L = 1.50 m Area = π * r^2 r = d/2 = 0.25 cm = 2.5 * 10^-3 m Area = π * (2.5 * 10^-3)^2
The cylindrical rod is similar to a resistor. Since the current is decreasing, the resistance must be increasing. This means the resistance is increasing as the temperature increases. Resistance = Voltage ÷ Current At 20˚, R = 15 ÷ 18.5 At 92˚, R = 15 ÷ 17.2
Now you know the resistance at the two temperatures. Let’s determine the resistivity at the two temperatures. Resistance = ρ * (L/A) ρ = Resistance * (A/L)
At 20˚, ρ = (15 ÷ 18.5) * [π * (2.5 * 10^-3)^2] ÷ 1.5 = At 92˚, ρ = (15 ÷ 17.2) * [π * (2.5 * 10^-3)^2] ÷ 1.5 =
Now you know the resistivity at the two temperatures. Let’s determine the temperature coefficient of resistivity for the material of the rod.
Rf = Ri * ([1 + α * (Tf – Ti)] Rf = 15 ÷ 17.2, Ri = 15 ÷ 18.5, Tf = 92˚, Ti = 20˚
15 ÷ 17.2 = 15 ÷ 18.5 * [1 + α * (92 – 20)] Multiply both sides by (18.5 ÷ 15) (18.5 ÷ 15) * (15 ÷ 17.2) = 1 + α * 72 Subtract 1 from both sides (18.5 ÷ 15) * (15 ÷ 17.2) – 1 = α * 72 Divide both sides by 72 α = 1.05 * 10^-3
Answer:
73.13°
Explanation:
According to snell's law,
n1sinθi = n2sinθr
n1/n2 = sinθr/sinθi
Critical angle is the angle of incidence at the denser medium when the angle of incidence at the less dense medium is 90°
This means i=C and r = 90°
The Snell's law formula will become
n1/n2 = sinC/sin90°
n2/n1 = 1/sinC
Where n1 is the refractive index of the less dense medium = 1.473
n2 is the refractive index of the denser medium = 1.540
Substituting the values in the formula,
1.540/1.473 = 1/sinC
1.045 = 1/sinC
SinC = 1/1.045
SinC = 0.957
C = sin^-1(0.957)
C = 73.13°
Horizontal velocity: 81.9 km/h
Vertical velocity: 57.4 km/h
Explanation:
We can solve this problem by resolving the velocity vector into its component along the horizontal and vertical direction.
The horizontal velocity of the stunt bike is given by:
where
v = 100 km/h is the magnitude of the velocity
is the angle of projection
Substituting, we find
The vertical velocity instead is given by
where
Substituting,
Learn more about vector components:
brainly.com/question/2678571
#LearnwithBrainly
