To correct number of significant figures!! (2.58 x 10^-2)(2.3 x 10^3)
————————————— = ?
5.68 x 10^3

*the ‘——‘ is a fraction symbol btw

2.58 rounded to 1 significant figure is 3. 2.3 rounded to one significant figure is 2 and 10^-2 is 0.01, which is the same if you round it to one significant figure. This is because when the first number that ISN'T a 0, you round it either up or down to 1 significant figure, and in this case, it is 0.01.

5.68 rounded to one significant figure is 6. 10 to the power of three is 1000, and 1000 doesn't need to be rounded to one significant figure. 3 x 0.01 is 0.03, and 2 x 1000 is 2000. 2000 x 0.03 is 60. 6 x 1000 is 6000. then you divide 60 by 6000, which is 0.01.

Explanation:

hope this helps you.

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.

at right angles to each other