Answer: 996m/s
Explanation:
Formula for calculating velocity of wave in a stretched string is
V = √T/M where;
V is the velocity of wave
T is tension
M is the mass per unit length of the wire(m/L)
Since the second wire is twice as far apart as the first, it will be L2 = 2L1
Let V1 and V2 be the speed of the shorter and longer wire respectively
V1 = √T/M1... 1
V2 = √T/M2... 2
Since V1 = 249m/s, M1 = m/L1 M2 = m/L2 = m/2L1
The equations will now become
249 = √T/(m/L1) ... 3
V2 = √T/(m/2L1)... 4
From 3,
249² = TL1/m...5
From 4,
V2²= 2TL1/m... 6
Dividing equation 5 by 6 we have;
249²/V2² = TL1/m×m/2TL1
{249/V2}² = 1/2
249/V2 = (1/2)²
249/V2 = 1/4
V2 = 249×4
V2 = 996m/s
Therefore the speed of the wave on the longer wire is 996m/s
Well, since you only want direction, ignore the numbers. Use the right hand rule.
Current (pointer finger) points west (left).
Magnetic field (middle finger) points south (towards you).
Force (thumb) then points up (away from the earth)
The distance between two particles that are <em>in phase</em>
What are you trying to here?
Answer:
a) that laser 1 has the first interference closer to the central maximum
c) Δy = 0.64 m
Explanation:
The interference phenomenon is described by the expression
d sin θ = m λ
Where d is the separation of the slits, λ the wavelength and m an integer that indicates the order of interference
For the separation of the lines we use trigonometry
tan θ = sin θ / cos θ = y / x
In interference experiments the angle is very small
tan θ = sin θ = y / x
d y / x = m λ
a) and b) We apply the equation to the first laser
λ = d / 20
d y / x = m d / 20
y = m x / 20
y = 1 4.80 / 20
y = 0.24 m
The second laser
λ = d / 15
d y / x = m d / 15
y = m x / 15
y = 0.32 m
We can see that laser 1 has the first interference closer to the central maximum
c) laser 1
They ask us for the second maximum m = 2
y₂ = 2 4.8 / 20
y₂ = 0.48 m
For laser 2 they ask us for the third minimum m = 3
In this case to have a minimum we must add half wavelength
y₃ = (m + ½) x / 15
m = 3
y₃ = (3 + ½) 4.8 / 15
y₃ = 1.12 m
Δy = 1.12 - 0.48
Δy = 0.64 m
