Answer:
2577 K
Explanation:
Power radiated , P = σεAT⁴ where σ = Stefan-Boltzmann constant = 5.6704 × 10⁻⁸ W/m²K⁴, ε = emissivity of bulb filament = 0.8, A = surface area of bulb = 30 mm² = 30 × 10⁻⁶ m² and T = operating temperature of filament.
So, T = ⁴√(P/σεA)
Since P = 60 W, we substitute the vales of the variables into T. So,
T = ⁴√(P/σεA)
= ⁴√(60 W/(5.6704 × 10⁻⁸ W/m²K⁴ × 0.8 × 30 × 10⁻⁶ m²)
= ⁴√(60 W/(136.0896 × 10⁻¹⁴ W/K⁴)
= ⁴√(60 W/(13608.96 × 10⁻¹⁶ W/K⁴)
= ⁴√(0.00441 × 10¹⁶K⁴)
= 0.2577 × 10⁴ K
= 2577 K
Answer:
6 km./hr.
Explanation:
Because 36 and 6 are rational numbers they can divided. So I divided 36 an 6 to come up with my answer
Hope this helps.
Answer:
6052114.67492 m
Explanation:
v = Velocity of cosmic ray = 0.88c
c = Speed of light =
d = Width of Earth = Diameter of Earth =
When the cosmic ray is moving towards Earth then in the frame of the cosmic ray the width of the Earth appears smaller than the original
This happens due to length contraction
Length contraction is given by
The Earth's width is 6052114.67492 m
Contraction only occurs in the cosmic ray's frame of reference in the direction of the ray. But in perpendicular direction the width remains unchanged.
Hence, the width is
Answer:
100 N force have to lift for the board to be carried
Explanation:
Given data
L = 3.00 m
F1 = 60.0 N
w = 160 N
to find out
magnitude F2 of force
solution
we know that F1 and F2 sum is equal to weight of board
so that we can say
F1 + F2 = W
so
F2 = W - F1
put the value W and F1
F2 = 160 - 60
F2 = 100 N
so 100 N force have to lift for the board to be carried
Answer: speed of light in solid = 1.88 * 10^8 m/s
Frequency is constant
Explanation: The relationship between the velocity of light wave and wavelength is given by the formulae below
V = fλ
During refraction, the frequency of light is constant, thus we have that
V = kλ which implies that velocity is proportional to wavelength.
Hence, we have that
v1/ λ1 = v2/ λ2
Where v1 = velocity of light in air = 3 * 10^8 m/s
v2 = velocity of sound in solid
λ1 = wavelength of light in air = 670nm
λ2 = wavelength of light in solid = 420nm
By making v2 subject of formulae, we have that
v2 = v1 * λ2/ λ1
v2 = 3 * 10^8 * 420nm/ 670nm
v2 = 3 * 10^8 * 0.6268
v2 = 1.88 * 10 ^8 m/s
b)
During refraction the frequency of light wave is constant this is because light consist of photons which has energy. it energy needs to be constant and for energy (E=hf) to be constant, frequency would be constant too.