Question

A LASER is a source of very intense, monochromatic, and unidirectional beam of light. These properties of a laser light can be exploited to measure long distances. The distance of the Moon from the Earth has been already determined very precisely using a laser as a source of light. A laser light beamed at the Moon takes 2.56 s to return after reflection at the Moonís surface. How much is the radius of the lunar orbit around the Earth ?
NCERT Solutions for Class 11 Physics Part 1 Chapter 2 Exercise 29

Answer 1

the radius of the lunar orbit is equal to the distance of the moon from the earth.therefore,
                 r = c*t/2
                   here c = 3×10 raise to power 8
                     t = 2.56 s
              therefore r = 3.84×10 raise to power 8 meter

Answer 2

==============ⓢⓦⓘⓖⓨ

$\huge\mathfrak\red{hello...frd\:swigy\:here}$

==============ⓢⓦⓘⓖⓨ

Time taken by the laser beam to return to Earth after reflection from the Moon = 2.56 s

Speed of light = 3 × 108 m/s

Time taken by the laser beam to reach Moon

=1/2 × 2.56 = 1.28 s

Radius of the lunar orbit

= Distance between the Earth and the Moon

= 1.28 × 3 × 108 = 3.84 × 108 m

= 3.84 × 105 km

I hope, this will help you

=======================

$<marquee behaviour-move bigcolour-pink><h1>☺ThankYou✌</h1></marquee>$

·.¸¸.·♩♪♫ ⓢⓦⓘⓖⓨ ♫♪♩·.¸¸.·

___________♦♦⭐♦ ♦___________