Answer:
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Sound created in a big hall will persist by repeated reflection from the walls until it is reduced to a value where it is no longer audible. The repeated reflection that results in this persistence of sound is called reverberation. In an auditorium or big hall excessive reverberation is highly undesirable
Explanation:
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Answer:c-The gravitational effect when spacecraft flies close to the asteriod
Explanation:
Gravitational effect on the spacecraft gives an estimate that how big is the asteroid by experiencing its gravitational pull.
The amount of extra thrust required to maintain the trajectory of the spacecraft during its motion hints at the scientist about the size of the asteroid.
Gravitational pull is directly proportional to the mass of object so greater the mass, greater will be the pull.
99% of the earth´s atmosphere by mass is made up of only these elements: Nitrogen and oxygen.
Answer: B) Nitrogen and oxygen.
Answer:
Explanation:
The change in potential energy can be expressed as:
where K is a constant with a value of 
, q1 and q2 are the charges of the proton and the electron and r is the distance between them.
The charge for the proton is 
and the charge for the electron is 
.
Converting r=1.0nm to m:
Replacing values:
Answer:
induced EMF = 240 V
and by the lenz's law direction of induced EMF is opposite to the applied EMF
Explanation:
given data
inductance = 8 mH
resistance = 5 Ω
current = 4.0 A
time t = 0
current grow = 4.0 A to 10.0 A
to find out
value and the direction of the induced EMF
solution
we get here induced EMF of induction is express as
E = - L 
...................1
so E = - L 
put here value we get
E = - 8 × 
E = -40 × 6
E = -240
take magnitude
induced EMF = 240 V
and by the lenz's law we get direction of induced EMF is opposite to the applied EMF
