Answer:
m g sin theta = force of object along incline due to gravity
N μ = frictional of incline on object where N is the normal force
N = m g cos theta force perpendicular to incline
m g sin theta = N μ = μ m g cos theta
μ = tan theta = tan 38 = .78
If it produces 20J of light energy in a second, then that 20J is the 10% of the supply that becomes useful output.
20 J/s = 10% of Supply
20 J/s = (0.1) x (Supply)
Divide each side by 0.1:
Supply = (20 J/s) / (0.1)
<em>Supply = 200 J/s </em>(200 watts)
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Here's something to think about: What could you do to make the lamp more efficient ? Answer: Use it for a heater !
If you use it for a heater, then the HEAT is the 'useful' part, and the light is the part that you really don't care about. Suddenly ... bada-boom ... the lamp is 90% efficient !
Answer:
0.0003 m = 0.3 mm
Explanation:
For constructive interference in the Young's experiment.
The position of the mth fringe from the central fringe is given by
y = L(mλ/d)
λ = wavelength = 720 nm = 720 × 10⁻⁹ m
L = distance between slits and screen respectively = 1.0 m
d = separation of slits = 0.68 mm = 0.68 × 10⁻³ m
m = 2
y = 1(2 × 720 × 10⁻⁹/(0.68 × 10⁻³) = 0.00212 m = 2.12 mm
For the 620 nm light,
y = 1(2 × 620 × 10⁻⁹/(0.68 × 10⁻³) = 0.00182 m = 1.82 mm
Distance apart = 2.12 - 1.82 = 0.3 mm = 0.0003 m
1.21 (this needs twenty so i have to write so yeah deal with it)
