A laser used in eye surgery emits a 2.95 mJ pulse in 1.18 ns, focused to a spot

Question

A laser used in eye surgery emits a 2.95 mJ pulse in 1.18 ns, focused to a spot 34.5 um in diameter on the retina. Calculate (in SI units) the power per unit area at the retina. (This quantity is called the irradiance.)

A laser used in eye surgery emits a 2,95 mJ pulse in 1.18 ns, focused to a spot 34.5 um in diameter on the retina. Calculate Cin SI units the power per unit area at the retina. This quantity is called the irradiance Submit Answer Tries 0/20 What energy is delivered to an area of molecular size say, a circular area 0.535 nm in diameter? submit Answer Tries 0/20

Explanation / Answer

Area = d2/ 4

d = 34.5 x 10^-6 meters

Area = 9.34 x 10^-10 m2

Energy = 2.95 x 10^-3 Joule

Time = 1.18 x 10^-9 sec.

Power = Energy/ time

= 2.5 x 10^6 joules/sec

Irradiance = Energy/ Area

=2.67 x10^15 j/sm2

(b)

Energy = Irradiance x Area

d' = 0.535x10^-9

Area' = 2.24 x 10^-19 m2

= 2.67 x10^15 x 2.24 x 10^-19

= 6 x10^-4 joules

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.