There is no factor on your list of choices that has any effect.
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:
a)θ=71.89°
b)NO
Explanation:
Given that
For glass n= 1.38
We know that for air n'=1
The angle for total internal reflection θc given as
sin θc=n'/n
By putting the values
sin θc=n'/n
sin θc=1/1.38
θc=46.43°
n'sinθ = n sinθref
sinθref = cosθc
n'sinθ = n cosθc
1 x sinθ =1.38 x cos 46.43°
θ=71.89°
b)
NO
Answer:
How long does the ball fall is t_2 = 13.66 (s).
From what height is the ball originally dropped is h= 913.90 (m).
Explanation:
Answer:
the correct answer is option C which is 50 units.
Explanation:
given,
two vector of magnitude = 30 units and of 70 units
to calculate resultants vector = \sqrt{a^2+b^2+2 a b cos\theta}
cos θ value varies from -1 to 1
so, resultant vector
=
a = 30 units and b = 70 units
=
= 40 units to 100 units
hence, the correct answer is option C which is 50 units.