The diagram is missing; however, we know that the intensity of a sound wave is inversely proportional to the square of the distance from the source:
where I is the intensity and r is the distance from the source.
We can assume for instance that the initial distance from the source is r=1 m, so that we put
The intensity at r=3 m will be
Therefore, the sound intensity has decreased by a factor
.
Answer: 1.3 ×10^-31
Explanation:
the required probability is P = e^(-2αL)
Firstly, evaluate (-2αL)
α= 1/hc √2mc^2 (U - E)
h= modified planck's constant
where,
(-2αL)
= -(2L)/(h/2π ) ×√2mc^2 (U - E)
= -(2L) / (hc^2/π )×√2mc^2 (U - E)
(hc^2/2pi) = 197*eV.nm (standard constant)
2*L = 8 nm
mc^2 = 0.511×10^6 eV
Where m = mass electron
C= speed of light
(-2αL) = [-8nm/(197 eV.nm)] × (1.022× 10^6 eV*×3 eV)^0.5
(-2αL) = -71.1
Probability = e^(-2αL) = e^-71.1 = 1.3 ×10^-31
Therefore, the probability that a ondu tion ele tron in one wire arriving at the gap will pass through the gap into the other wire 1.3 ×10^-31.
The correct statements are that the speed decreases as the distance decreases and speed increases as the distance increases for the same time.
Answer:
Option A and Option B.
Explanation:
Speed is defined as the ratio of distance covered to the time taken to cover that distance. So Speed = Distance/Time. In other words, we can also state that speed is directly proportional to the distance for a constant time. Thus, the speed will be decreasing as there is decrease in distance for the same time. As well as there will be increase in speed as the distance increases for the same time. So option A and option B are the true options. So if there is decrease in the distance due to direct proportionality the speed will also be decreasing. Similarly, if the distance increases, the speed will also be increasing.
Answer:
7revolutions
Explanation:
Given parameters:
Initial revolution = 250rpm
Final revolution = 150rpm
Time = 4.2s
Unknown:
Number of revolutions that occur at this time = ?
Solution:
To solve this problem;
let us find the change in revolution = 250rpm - 150rpm = 100rpm
Convert the time to seconds;
60s makes 1 minute
4.2s will make 
= 0.07min
So;
The number of revolutions at this time = 100rpm x 0.07min
= 7revolutions
