Answer:
Constructive interference
Explanation:
Here, the medium is same, same wavelength, same frequency, same amplitude and same direction of propagation.
Let the intensity of waves be I which is same for both
The formula for the net intensity is

where, Ф be the phase difference
So, 
Here, IR is maximum so the interference is constructive in nature.
Answer:
0.775
Explanation:
The weight of an object on a planet is equal to the gravitational force exerted by the planet on the object:

where
G is the gravitational constant
M is the mass of the planet
m is the mass of the object
R is the radius of the planet
For planet A, the weight of the object is

For planet B,

We also know that the weight of the object on the two planets is the same, so

So we can write

We also know that the mass of planet A is only sixty percent that of planet B, so

Substituting,

Now we can elimanate G, MB and m from the equation, and we get

So the ratio between the radii of the two planets is

Answer:

Explanation:
Refraction: It is a process in which light ray travel from one medium to another medium.
When a light travel form one medium to another medium then the speed of light changes.
When a light travel from rare to denser medium then the light bend towards normal .
When a light travel form denser to rare medium then the light ray bend away from the normal.
Refractive index:It is a ratio of velocity of light in vacuum to the velocity of light in medium .It is a measure of change in speed of light when it passes from vacuum into material.It is represented by "n''.
Mathematical representation:

Where n=Refractive index of material
c=Velocity of light in vacuum
v=Velocity of light in medium
<span>
The needle of a compass will always lies along the magnetic
field lines of the earth.
A magnetic declination at a point on the earth’s surface
equal to zero implies that
the horizontal component of the earth’s magnetic field line
at that specific point lies along
the line of the north-south magnetic poles. </span>
The presence of a
current-carrying wire creates an additional <span>
magnetic field that combines with the earth’s magnetic field.
Since magnetic
<span>fields are vector quantities, therefore the magnetic field of
the earth and the magnetic field of the vertical wire must be
combined vectorially. </span></span>
<span>
Where:</span>
B1 = magnetic field of
the earth along the x-axis = 0.45 × 10 ⁻ ⁴ T
B2 = magnetic field due to
the straight vertical wire along the y-axis
We can calculate for B2
using Amperes Law:
B2 = μ₀ i / [ 2 π R ]
B2 = [ 4π × 10 ⁻ ⁷ T • m / A ] ( 36 A ) / [ 2 π (0.21 m ) ] <span>
B2 = 5.97 × 10 ⁻ ⁵ T = 0.60 × 10 ⁻ ⁴ T </span>
The angle can be
calculated using tan function:<span>
tan θ = y / x = B₂ / B₁ = 0.60 × 10 ⁻ ⁴ T / 0.45 × 10 ⁻ ⁴ T <span>
tan θ = 1.326</span></span>
θ = 53°
<span>
<span>The compass needle points along the direction of 53° west of
north.</span></span>