Question

Известно, что в стекле скорость распространения света в 1,48 раз(-а) меньше, чем в вакууме. Какова толщина стеклянной пластинки, если за5,2⋅10−9 с нормально падающий луч успевает достигнуть нижней грани пластины, отразиться и вернуться назад. Ответ (округли до десятых): дм.

Answer 1

Дано:

с = 3*10⁸ м/с

v = c/1,48

t = 5,2*10-9 c

1 дм = 10 см = 0,1 м

d - ?

Решение:

Путь луча до нижней грани равен d, обратный также равен d. Тогда весь путь равен 2d. Весь путь луч проходит за время t со скоростью v:

2d = v*t => d = vt/2 = v*(t/2), т.к. v = c/1,48, то:

d = (c/1,48)*(t/2) = (3*10⁸/1,48)*(5,2*10-9/2) = 0.52702702703 = 0,53 м = 5,3 дм

Ответ: 5,3 дм.

Answer 2

Calculation of the Thickness of the Glass Plate

To calculate the thickness of the glass plate, we need to consider the time it takes for the light to travel through the glass and reflect back.

Given: - Speed of light in vacuum: c = 3.00 x 10^8 m/s - Speed of light in glass: v = 1.48 x c

Let's assume the thickness of the glass plate is d.

The time it takes for the light to travel through the glass and reflect back can be calculated using the formula:

t = (2d/v)

We are given that the time taken is 5.2 x 10^-9 s.

Substituting the given values into the formula, we get:

5.2 x 10^-9 s = (2d)/(1.48 x c)

Simplifying the equation, we can solve for d:

d = (5.2 x 10^-9 s) x (1.48 x c) / 2

Now, let's calculate the value of d.

Using the given value for the speed of light in vacuum, c = 3.00 x 10^8 m/s, we can substitute the values into the equation:

d = (5.2 x 10^-9 s) x (1.48 x (3.00 x 10^8 m/s)) / 2

Calculating this expression, we find:

d ≈ 2.44 x 10^-4 m

Converting this value to decimeters (dm), we get:

d ≈ 0.0244 dm

Therefore, the thickness of the glass plate is approximately 0.0244 dm (rounded to the nearest tenth).

Please note that the calculation assumes the light travels in a straight line through the glass plate and reflects back without any loss or dispersion.