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Lina20 [59]
2 years ago
15

LASIK eye surgery uses pulses of laser light to shave off tissue from the cornea, reshaping it. A typical LASIK laser emits a 1.

0-mm-diameter laser beam with a wavelength of 193 nm. Each laser pulse lasts 20 ns and contains 2.0 mJ of light energy.
Part A: What is the power of one laser pulse?
Part B: During the very brief time of the pulse, what is the intensity of the light wave?
Physics
1 answer:
pickupchik [31]2 years ago
6 0

Answer:

a)     P = 1.0 10⁵ W, b)   I = 1.27 10¹¹ W / m²

Explanation:

a) the power is defined by the unit of time work

       P = W / t

Work is equal to the variation of energy

       P = E / t

Let's calculate

      P = 2.0 10⁻³ / 20 10⁻⁹

      P = 1.0 10⁵ W

b) intensity is defined as the ratio between power per area unit

      I = P / A

The area of a circle is

     A = π r²

     r = d / 2

     A = π (0.5 10⁻³)²

     A = 0.785 10⁻⁶ m²

     I = 1.0 10⁵ / 0.786 10⁻⁶

     I = 1.27 10¹¹ W / m²

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2 t of ferrous scrap at a temperature of 20 degrees is heated to the melting point and melted. How much to consume?
photoshop1234 [79]

Answer

Calculate the amount of heat needed to melt 2.00 kg of iron at its melting point (1809 K), given that: ?Hfus = 13.80

3 0
2 years ago
A proton with charge 1.602 x 10^-19 C moves at a speed of 300 m/s in a magnetic field at an angle of 65 degrees. If the strength
soldi70 [24.7K]

Answer:

F_m= 8.28 \times 10^{-16} N

Explanation:

The magnitude of the force is F_m=evB\sin\theta\\\implies F_m=1.602 \times 10^{-19}\times 300\times 19\times\sin 65^0= 8.28 \times 10^{-16} N

3 0
2 years ago
A cart of mass 6.0 kg moves with a speed of 3.0 m/s towards a second stationary cart with a mass of 3.0 kg. The carts move on a
katen-ka-za [31]

Answer:b

Explanation:

Given

mass of first cart m_1=6 kg

mass of second cart m_2=3 kg

velocity of first cart v_1=3 m/s

conserving momentum

m_1v_1+m_2v_2=(m_1+m_2)v

6\times 3+3\times 0=(9)\cdot v

v=2 m/s

Initial kinetic Energy K.E._1=\frac{1}{2}m_1v_1^2+\frac{1}{2}m_2v_2^2

K.E._1=\frac{1}{2}\cdot 6\cdot 3^2+0

K.E._1=27 J

Final Kinetic Energy

K.E._2=\frac{1}{2}(m_1+m_2)v^2

K.E._2=\frac{1}{2}(6+3)\cdot 2^2=18 J

Ratio of initial Kinetic Energy to the Final Kinetic Energy

=\frac{27}{18}=1.5

6 0
3 years ago
A 100 N force is applied to move an object a horizontal distance of 5 meters at constant speed in 10 seconds. How much power is
Tpy6a [65]

Answer:

50 W

Explanation:

<h3><u>Given :</u></h3>

  • Force applied = 100 N
  • Distance covered = 5 metres
  • Time = 10 seconds

<h3><u>To find :</u></h3>

Power

<h3><u>Solution :</u></h3>

For calculating power, we first need to know about the work done.

\bf \boxed{Work = Force \times displacement}

Now, substituting values in the above formula;

Work = 100 × 5

= 500 Nm or 500 J

We know that,

\bf \boxed{Power=\dfrac{Work\:done}{Time\: taken}}

Substituting values in above formula;

Power = 500/ 10

= 50 Nm/s or 50 W

Hence, power = 50 W .

5 0
3 years ago
A Smart Car, which has a mass of 1000 kg, is going 20 m/s. When it hits the barrier, it stops with a time of 0.5 seconds. What i
Fudgin [204]

Answer:

need points sorry god bless

Explanation:

3 0
3 years ago
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