The bimetallic strip in a fire alarm is made of two metals with different expansion rates bonded together to form one piece of metal. Typically, the low-expansion side is made of a nickel-iron alloy called Invar, while the high-expansion side is an alloy of copper or nickel. The strip is electrically energized with a low-voltage current. When the strip is heated by fire, the high-expansion side bends the strip toward an electrical contact. When the strip touches that contact, it completes a circuit that triggers the alarm to sound. The width of the gap between the contacts determines the temperature that will set off the alarm.
The two components of projectile motion include the following:
<h3>What is a Projectile?</h3>
This is defined as a missile propelled by the application of an external force and allowed to move freely under the influence of gravity and air resistance.
The equation for Horizontal motion Vx = V * cos(α)
Vertical velocity component: Vy = V * sin(α)
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Answer:

Explanation:
From the question we are told that:
Frequency of 3rd harmonics 
Frequency of 5th harmonics 
Generally the equation for Wavelength at 3rd Harmonics is mathematically given by

Therefore

Generally the equation for Wavelength at 1st Harmonics is mathematically given by

Therefore

Generally the equation for the frequency of the first harmonic is mathematically given by



Answer:
The number is 
Explanation:
From the question we are told that
The wavelength is 
The length of the glass plates is 
The distance between the plates (radius of wire ) = 
Generally the condition for constructive interference in a film is mathematically represented as
![2 * t = [m + \frac{1}{2} ]\lambda](https://tex.z-dn.net/?f=2%20%2A%20%20t%20%20%3D%20%5Bm%20%2B%20%20%5Cfrac%7B1%7D%7B2%7D%20%20%5D%5Clambda)
Where t is the thickness of the separation between the glass i.e
t = 0 at the edge where the glasses are touching each other and
t = 2d at the edge where the glasses are separated by the wire
m is the order of the fringe it starts from 0, 1 , 2 ...
So
![2 * 2 * d = [m + \frac{1}{2} ] 520 *10^{-9}](https://tex.z-dn.net/?f=2%20%2A%20%202%20%2A%20d%20%20%20%3D%20%5Bm%20%2B%20%20%5Cfrac%7B1%7D%7B2%7D%20%20%5D%20520%20%2A10%5E%7B-9%7D)
=> ![2 * 2 * (2.8 *10^{-5}) = [m + \frac{1}{2} ] 520 *10^{-9}](https://tex.z-dn.net/?f=2%20%2A%20%202%20%2A%20%20%20%282.8%20%2A10%5E%7B-5%7D%29%20%3D%20%5Bm%20%2B%20%20%5Cfrac%7B1%7D%7B2%7D%20%20%5D%20520%20%2A10%5E%7B-9%7D)
=>

given that we start counting m from zero
it means that the number of bright fringes that would appear is

=> 
=> 