If I0 = 10-12 W/m2 is the threshold of hearing, a sound with intensity I1 = 10-10 W/m2 will give a certain decibel level. Suppose a new sound has an intensity I2 = I12/I0 . What is the new decibel level?
a. 40
c. 10,000
b. 20
d. It will square the decibel level.
A
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A mass is pressed against (but is not attached to) an ideal horizontal spring on a frictionless horizontal surface. After being released from rest, the mass acquires a maximum speed v and a maximum kinetic energy K
If instead the mass initially compresses the spring twice as far: A) Its maximum speed will be 2v and its maximum kinetic energy will be 2K. B) Its maximum speed will be 2v and its maximum kinetic energy will be K. C) Its maximum speed will be v and its maximum kinetic energy will be 2K. D) Its maximum speed will be 2v and its maximum kinetic energy will be 4K. E) Its maximum speed will be 4v and its maximum kinetic energy will be 2K.
The major processes that heat the interiors of the terrestrial worlds are
A) (1 ) Heat deposited as the planets were built from planetesimals; (2 ) heat of accretion; (3 ) heat that came from the gravitational potential energy of incoming planetesimals. B) (1 ) Heat of accretion; (2 ) heat from convection; (3 ) heat from thermal radiation. C) (1 ) Heat deposited as the planets were built from planetesimals; (2 ) heat deposited as the planets underwent differentiation; (3 ) heat released by radioactive decay. D) (1 ) Volcanism; (2 ) tectonics; (3 ) erosion.
Instructions: On occasion, the notation 
will be a shorthand notation for 
.
If 
= [15, 80°] and 
, what is the magnitude of 
?
A. 15
B. 35
C. 32
D. 5.0
E. 23
Which of the following combinations of circuit components can be used to make a tuner for a radio, to select the desired frequency?
a. fixed inductor, variable resistor b. fixed resistor, variable inductor c. fixed inductor, variable capacitor d. fixed capacitor, variable resistor