The best and most correct answers among the choices provided by your question are he second and third choices.
<span>The velocity at any instant the average velocity during some time interval cannot be obtained from the graph alone.</span>
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Answer:

Explanation:
Given:
- wavelength of light in the air,

- time taken to travel from the source to the photocell via air,

- time taken to reach the photocell via air and glass slab,

- thickness of the glass slab,

<u>Now we have the relation for time:</u>

hence,

c= speed of light in air



For the case when glass slab is inserted between the path of light:
(since light travel with the speed c only in the air)
here:
v = speed of light in the glass


Using Snell's law:



Answer:
d = 2,042 10-3 m
Explanation:
The laser diffracts in the circular slit, so the process equation is
d sin θ= m λ
The first diffraction minimum occurs for m = 1
We can use trigonometry in the mirror
tan θ = Y / L
Where L is the distance from the Moon to Earth
Since the angle is extremely small
tan θ = sin θ / cos θ
Cos θ = 1
tant θ = sin θ = y / L
We replace
d y / L = λ
d = λ L / y
Let's calculate
d = 532 10⁻⁹ 3.84 10⁶/1 10³
d = 2,042 10-3 m
Answer:
4.98 m
Explanation:
Given that
Width of the mirror, d = 0.6 m
Organist distance to the mirror, s = 0.78 m
Distance between the singer and the organist, S = 5.7 + 0.78 = 6.48 m
Width of north wall, D?
Using the simple relationship
D/S = d/s, on rearranging
D = dS /s
D = (0.6 * 6.48) / 0.78
D = 3.888 / 0.78
D = 4.98 m
Therefore, we can conclude that the Width of north wall is 4.98 m
Before getting an answer for it first we have to understand nuclear fusion.
Nuclear fusion is a thermo-nuclear reaction in which two light unstable nuclei will form a heavy stable nuclei. In this process there will be some mass defect which will be converted into energy as per Einstein's mass energy equivalence theorem.
The theorem is stated as
where c is the velocity of light and m is the mass converted into energy.
One take an example of fusion in sun where 4 hydrogen atoms combine to form a helium nucleus which are explained below-



-----------------------------------------------------------------------
Here
is the positron.
In this process very high temperature is needed which is approximately equal to the temperature of the sun i.e 
Such temperature is very difficult to initiate the reaction on the earth surface. It should be carried out in an sustainable way also .Otherwise It will cause nuclear hazards.