Answer:
λ = 470.66 nm
Explanation:
for bright fringe
D= distance between slit and screen
d= distance between the slits
for first order bright fringe m = 1,


for dark fringe,we have
Now to get the dark fringes at the same location we should have;
(706)D/d = (m + 1/2)λD/d
put m = 1
(1 + 1/2)λ = (706)
λ = 470.66 nm
You should rest as much as possible
Explanation:
In order to compute correctly the sum of the two terms, we have to rewrite one of them such that they have the same exponent.
The two terms are:


For instance, we can re-write the second term such as it also has a power
. In order to do that, we have to move the decimal point one place to the left, therefore:

At this point, the two numbers have the same exponent, so we can just add them together by adding the bases and keeping the same exponent, -2:

Answer:
ρ_body = 1000 kg / m³
Explanation:
This is an exercise in fluid mechanics, specifically we must use the Archimedean principle, which states that the thrust is equal to the weight of the dislodged liquid.
In this case let's start by finding the volume of our body
oak block
v = l to h
v = 0.02 0.02 0.05
V = 2 10⁻⁵ m³
cooper block indicate that it has the same dimensions so its volume is the same, the total volume of the body is
V_total = 4 10⁻⁵ m³
as they indicate that the body is fully submerged there is a balance between weight and thrust
B - W = 0
the push is
B = ρ_fluid g V_total
the body weight is
ρ_body = M / V_total
M = ρ_body V_total
W = Mg
W = ρ_body V_total g
we substitute
ρ_fluid g V_total = ρ_body V_total g
ρ_body = ρ_fluid
in this case the body is in equilibrium in the fluid, in case the density of the body is greater than that of the fluid, the body sinks
Therefore the average density is equal to the density of the fluid, since since it is water the density is
ρ_body = 1000 kg / m³