When a high-power laser is used in the Earth's atmosphere, the electric field associated with the laser beam can ionize the air,
turning it into a conducting plasma that reflects the laser light. In dry air at 0°C and 1 atm, electric breakdown occurs for fields with amplitudes above about 3.00 MV/m.
(a) What laser beam intensity will produce such a field?
W/m2
(b) At this maximum intensity, what power can be delivered in a cylindrical beam of diameter 3.44 mm?
W
(a) What laser beam intensity will produce such a field?
W/m2
(b) At this maximum intensity, what power can be delivered in a cylindrical beam of diameter 3.44 mm?
W
1 answer:
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The complete question is missing, so i have attached the complete question.
Answer:
A) FBD is attached.
B) The condition that must be satisfied is for ω_min = √(g/r)
C) The tension in the string would be zero. This is because at the smallest frequency, the only radially inward force at that point is the weight(force of gravity).
Explanation:
A) I've attached the image of the free body diagram.
B) The formula for the net force is given as;
F_net = mv²/r
We know that angular velocity;ω = v/r
Thus;
F_net = mω²r
Now, the minimum downward force is the weight and so;
mg = m(ω_min)²r
m will cancel out to give;
g = (ω_min)²r
(ω_min)² = g/r
ω_min = √(g/r)
The condition that must be satisfied is for ω_min = √(g/r)
C) The tension in the string would be zero. This is because at the smallest frequency, the only radially inward force at that point is the weight(force of gravity).
