Answer:
0.002925 m
Explanation:
Lt = LO(1 +α Δt ) here Lt is total length Lo is original length α is coefficient of linear expansion and Δt is change in temperature
<h2>for aluminium</h2>
α=25×10^-6
Lt = 5(1+25×10^-6×(70-20))
Lt = 5 (1+25×10^-6×50)
Lt = 5 ( 1+0.00125)
Lt = 5×1.00125
Lt =5.00625 m
<h2>for nickel </h2>
α=13.3×10^-6
Lt =5(1+13.3×10^-6×50)
Lt = 5(1+0.000665)
Lt =5.003325 m
hence difference in length =5.00625-5.003325
= 0.002925 m
When air is blown into the open pipe,
L = 
where nis any integral number 1,2,3,4 etc. and λ is the wavelength of the oscillation
⇒λ=
Note here that n=1 is for fundamental, n=2 is first harmonic and so on..
⇒ third harmonic will be n=4
Given L=6m, n=4, solving for λ we get:
λ=
=3m
Relationship of frequency(f), velocity of sound (c) and wavelength(λ) is:
c=f.λ Or f= 
⇒f=
≈115 Hz
Answer:
The correct option is C
Explanation:
The pendulum bob would return at the same time because the initial angle a pendulum bob is dropped does not affect it's period (the time it takes for the pendulum to move back and forth), however the one with a larger angle move faster but would eventually arrive at the same "starting point" due to varying displacements made.
Answer:
(B) (length)/(time³)
Explanation
The equation x = ½ at² + bt³ has to be dimensionally correct. In other words the term bt³ and ½ at² must have units of change of position = length.
We solve in order to find the dimension of b:
[x]=[b]*[t]³
length=[b]*time³
[b]=length/time³
