Answer:
Time period between the successive beats will be 0.1703 sec
Explanation:
We have given speed of the sound v = 349 m/sec
Wavelength of piano 
Wavelength of piano 
So frequency of piano A 
Frequency of piano B 
So beat frequency f = 455.61 - 449.74 = 5.87 Hz
So time period 
So time period between the successive beats will be 0.1703 sec
Answer:

Explanation:
Given data

To find
Mutual inductance of the two-coil system
Solution
The mutual inductance given as:
M= (-VΔt)/ΔI
Substitute the given values
So

Answer:
The magnetic flux through a loop is zero when the B field is perpendicular to the plane of the loop.
Explanation:
Magnetic flux are also known as the magnetic line of force surrounding a bar magnetic in a magnetic field.
It is expressed mathematically as
Φ = B A cos(θ) where
Φ is the magnetic flux
B is the magnetic field strength
A is the area
θ is the angle that the magnetic field make with the plane of the loop
If B is acting perpendicular to the plane of the loop, this means that θ = 90°
Magnetic flux Φ = BA cos90°
Since cos90° = 0
Φ = BA ×0
Φ = 0
This shows that the magnetic flux is zero when the magnetic field strength B is perpendicular to the plane of the loop.