Two loudspeakers L, and L2 driven from a common oscillator are arranged as shown in the diagram. A detector is placed at D. It is found that, as the frequency of the oscillator
is gradually changed from 200 Hz to 1000 Hz the detected signal passes through a series
of maxima and minima.

(a) Explain why this is so.
(b) Calculate the frequency at which the first
minimum above 200 Hz is observed.
D
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If an object with an initial temperature of 300 k increases its temperature by 1°c every minute, by how many degrees fahrenheit will its temperature have increased in 10 minutes? (a) 6°f (b) 10°f (c) 18°f (d) 30°f

Suppose you increase your walking speed from 7 m/s to 13 m/s in a period of 2 s. what is your acceleration?

Two conductors, a and b, are each in the shape of a tetrahedron. but of different sizes. they are charged in the following manner: 1. tetrahedron a is charged from an electrostatic generator to charge q. 2. tetrahedron a is briefly touched to tetrahedron b. 3. steps 1 and 2 are repeated until the charge on tetrahedron b reaches a maximum value. if the charge on tetrahedron b was q/4 after the first time it touched tetrahedron a. what is the final charge qbmax on tetrahedron b?