Home
Class 11
PHYSICS
The noise level in a classroom in absenc...

The noise level in a classroom in absence of the teacher is 50 dB when 50 students are present. Assuming that on the average each student outputs same sound energy per second, what will be the noise level if the number of students is increased to 100 ?

Text Solution

Verified by Experts

The correct Answer is:
B, C, D
Let the intensity of each student be I.
According to the question
`beta_A=10 log_10((50I)/I_0)`
`beta_B=10 log_10((100I)/I_0)`
`rarr beta_B-beta_A`
`=10 log_10((100I)/I_0)-10log_10((50I)/I_0)`
=10log((100I)/(50I))`
` =10log_102=3`
so, beta_A=50+3=53dB`
Promotional Banner

Similar Questions

Explore conceptually related problems

A student performs an experiment to determine how the range of a ball depends on the velocity with which it is projected. The "range" is the distance between the points where the ball lends and from where it was projected, assuming it lands at the same height from which it was projected. It each trial, the student uses the same baseball, and launches it at the same angle. Table shows the experimental results. |{:("Trail","Launch speed" (m//s),"Range"(m)),(1,10,8),(2,20,31.8),(3,30,70.7),(4,40,122.5):}| Based on this data, the student then hypothesizes that the range, R, depends on the initial speed v_(0) according to the following equation : R=Cv_(0)^(n) , where C is a constant and n is another constant. The student performs another trial in which the ball is launched at speed 5.0 m//s . Its range is approximately:

A student noted the number of cars passing through a spot on a road for 100 periods each of 3 minutes and summarised it in the table given below. Find the mode of the data . {:("Number of cars ",0-10,10-20,20-30,30-40,40-50,50-60,60-70,70-80),("Frequency "," "7," "14," "13," "12," "20," "11," "15," "8):}