Answer:
0.04973 W
Explanation:
I = Intensity of laser =
(assumed, as it is not given)
d = Diameter of spot = 1.31 mm
r = Radius = 
A = Area = 
Power is given by

The power output of the laser is 0.04973 W
Complete Question
A spherical wave with a wavelength of 2.0 mm is emitted from the origin. At one instant of time, the phase at r_1 = 4.0 mm is π rad. At that instant, what is the phase at r_2 = 3.5 mm ? Express your answer to two significant figures and include the appropriate units.
Answer:
The phase at the second point is 
Explanation:
From the question we are told that
The wavelength of the spherical wave is 
The first radius is 
The phase at that instant is 
The second radius is 
Generally the phase difference is mathematically represented as

this can also be expressed as

So we have that

substituting values



is the magnitude of the magnetic field made by the current
<u>Explanation:</u>
Given data:

Magnetic field of earth, 
We need to find the magnetic field of wire, 
The compass needle moves toward a direction of magnetic field. The current in wire makes a magnetic field in available space where the compass is on the ground. The vector sum of the Earth's magnetic field and the wire's magnetic field represents the net magnetic field, as shown in the attached drawing, expressing the angle:

By substituting the given values, we get


Answer:
x = 259 Hz
Explanation:
given,
frequency of one tuning fork = 250 Hz
frequency of another tuning fork = 266 Hz
when a tuning fork is sounded together beat frequency heard = 9
let x be the frequency of unknown
x - 250 = 9 Hz..............(1)
x = 259 Hz
when a another tuning fork is sounded together beat frequency heard = 7
266 - x = 7 Hz..............(2)
x = 259 Hz
now, on solving both the equation the frequency comes out to be 259 Hz.
so, The frequency of the tuning fork is equal to 259 Hz
Answer:
576 joules
Explanation:
From the question we are given the following:
weight = 810 N
radius (r) = 1.6 m
horizontal force (F) = 55 N
time (t) = 4 s
acceleration due to gravity (g) = 9.8 m/s^{2}
K.E = 0.5 x MI x ω^{2}
where MI is the moment of inertia and ω is the angular velocity
MI = 0.5 x m x r^2
mass = weight ÷ g = 810 ÷ 9.8 = 82.65 kg
MI = 0.5 x 82.65 x 1.6^{2}
MI = 105.8 kg.m^{2}
angular velocity (ω) = a x t
angular acceleration (a) = torque ÷ MI
where torque = F x r = 55 x 1.6 = 88 N.m
a= 88 ÷ 105.8 = 0.83 rad /s^{2}
therefore
angular velocity (ω) = a x t = 0.83 x 4 = 3.33 rad/s
K.E = 0.5 x MI x ω^{2}
K.E = 0.5 x 105.8 x 3.33^{2} = 576 joules